Hiroshi Ishikita, Giulia Morra, and Ernst-Walter Knapp* Biochemistry 42 (2003) 3882-3892. doi: 10.1021/bi026781t “Redox potential of quinones in photosynthetic reaction centers from Rhodobacter sphaeroides: dependence on protonation of Glu-L212 and Asp-L213″ JournalPubMed
Hiroshi Ishikita and Ernst-Walter Knapp* J. Biol. Chem. 278 (2003) 52002-52011. doi: 10.1074/jbc.M306434200 “Redox potential of quinones in both electron transfer branches of photosystem I” JournalPubMed
Hiroshi Ishikita and Ernst-Walter Knapp* J. Am. Chem. Soc. 126 (2004) 8059-8064. doi: 10.1021/ja038092q “Variation of Ser-L223 Hydrogen bond between Ser-L223 and QB–: protonation of Asp-L213 in the reaction center of Rhodobacter sphaeroides“ JournalPubMed
Hiroshi Ishikita, Bernhard Loll, Jacek Biesiadka, Artur Galstyan, Wolfram Saenger and Ernst-Walter Knapp* FEBS Lett. 579 (2005) 712-716. doi: 10.1016/j.febslet.2004.12.049 “Tuning electron transfer by ester-group of chlorophylls in bacterial photosynthetic reaction center” JournalPubMed
Hiroshi Ishikita and Ernst-Walter Knapp J. Am. Chem. Soc. 127 (2005) 1963-1968. doi: 10.1021/ja045058i “Redox potentials of chlorophylls and β-carotene in the antenna complexes of photosystem II” JournalPubMed
Hiroshi Ishikita and Ernst-Walter Knapp* J. Biol. Chem. 280 (2005) 12446-12450. doi: 10.1074/jbc.M413531200 “Energetics of proton transfer pathways in reaction centers from Rhodobacter sphaeroides. The Glu-H173 activated mutants” JournalPubMed
Hiroshi Ishikita, Bernhard Loll, Jacek Biesiadka, Wolfram Saenger and Ernst-Walter Knapp Biochemistry 44 (2005) 4118-4124. doi: 10.1021/bi047922p “Redox potentials of chlorophylls in the photosystem II reaction center” JournalPubMed
Hiroshi Ishikita and Ernst-Walter Knapp* FEBS Lett. 579 (2005) 3190-3194. doi: 10.1016/j.febslet.2005.05.004 “Redox potential of cytochrome c550 in the cyanobacterium Thermosynechococcus elongatus“ JournalPubMed
Hiroshi Ishikita and Ernst-Walter Knapp* J. Am. Chem. Soc.127 (2005) 14714-14720. doi: 10.1021/ja052567r “Control of quinone redox potentials in photosystem II: electron transfer and photoprotection” JournalPubMed
Hiroshi Ishikita and Ernst-Walter Knapp* Biochemistry 44 (2005) 14772-14784. doi: 10.1021/bi051099v “Oxidation of the non-heme iron complex in photosystem II” JournalPubMed
Hiroshi Ishikita and Ernst-Walter Knapp* Proc. Natl. Acad. Sci. U. S. A.102 (2005) 16215-16220. doi: 10.1073/pnas.0503826102 [Direct Submission, Edited by H. Gray] “Induced conformational changes upon Cd2+ binding at photosynthetic reaction centers” JournalPubMed
Hiroshi Ishikita, Dietmar Stehlik, John H. Golbeck and Ernst-Walter Knapp* Biophys. J. 90 (2006) 1081-1089. doi: 10.1529/biophysj.105.069781 “Electrostatic influence of PsaC protein binding to the PsaA/PsaB heterodimer in Photosystem I” JournalPubMed
Hiroshi Ishikita, Wolfram Saenger, Bernhard Loll, Jacek Biesiadka, and Ernst-Walter Knapp* Biochemistry 45 (2006) 2063-2071. doi: 10.1021/bi051615h “Energetics of a possible proton exit pathway for water oxidation in Photosystem II” JournalPubMed
Hiroshi Ishikita, Jacek Biesiadka, Bernhard Loll, Wolfram Saenger, and Ernst-Walter Knapp* Angew. Chem. 118 (2006) 1998-1999. doi: 10.1002/anie.200503804 Angew. Chem. Int. Ed. 45 (2006) 1964-1965 doi: 10.1002/anie.200503804 “Cationic state of accessory chlorophyll and electron transfer through pheophytin to plastoquinone in photosystem II” JournalPubMed
Hiroshi Ishikita and Ernst-Walter Knapp* Biophys. J. 90 (2006) 3886-3896. doi: 10.1529/biophysj.105.076984 “Function of redox-active tyrosine in photosystem II” JournalPubMed
Hiroshi Ishikita, Wolfram Saenger, Jacek Biesiadka, Bernhard Loll, and Ernst-Walter Knapp* Proc. Natl. Acad. Sci. U. S. A. 103 (2006) 9855-9860. [Direct Submission, Edited by H. Gray] doi: 10.1073/pnas.0601446103 “How photosynthetic reaction centers control oxidation power in chlorophyll pairs P680, P700 and P870” JournalPubMed
Hiroshi Ishikita and Ernst-Walter Knapp* FEBS Lett. 580 (2006) 4567-4570. doi: 10.1016/j.febslet.2006.07.023 “Electrostatic role of the non-heme iron complex in bacterial photosynthetic reaction center” JournalPubMed
Hiroshi Ishikita*, Bernhard Loll, Jacek Biesiadka, Jan Kern, Klaus-Dieter Irrgang, Athina Zouni, Wolfram Saenger and Ernst-Walter Knapp Biochim. Biophys. Acta (Bioenergetics) 1767 (2007) 79-87. doi: 10.1016/j.bbabio.2006.10.006 “Function of two beta-carotenes near the D1 and D2 proteins in photosystem II dimers” JournalPubMed
Hiroshi Ishikita* and Ernst-Walter Knapp J. Am. Chem. Soc.129 (2007) 1210-1215. doi: 10.1021/ja066208n “Protonation states of ammonia/ammonium in the hydrophobic pore of ammonia transporter protein AmtB” JournalPubMed
Irina Karygina, Dietmar Stehlik, Ingelog Wyndhamn, Art van der Est, Hiroshi Ishikita, Ernst-Walter Knapp, Barath Jaganathan, Rufat Agalarov, and John H. Golbeck* Biochemistry 46 (2007) 10804-10816. “Contributions of the distant protein environment to the redox potentials of the A1 phylloquinone and the FX iron-sulfur cluster in photosystem I” JournalPubMed
Hiroshi Ishikita, Alexander V. Soudackov, and Sharon Hammes-Schiffer* J. Am. Chem. Soc.129 (2007) 11146-11152. doi: 10.1021/ja072708k “Buffer-assisted proton-coupled electron transfer in a model rhenium-tyrosine complex” JournalPubMed
Hiroshi Ishikita* FEBS Lett.581 (2007) 4293-4297. doi: 10.1016/j.bbabio.2007.08.004 “Modulation of the protein environment in the hydrophilic pore of the ammonia transporter protein AmtB upon the GlnK protein binding” JournalPubMed
Hiroshi Ishikita* J. Biol. Chem. 282 (2007) 25240-25246. “Influence of the protein environment on the redox potentials of flavodoxins from Clostridium beijerinckii“ JournalPubMed
Hiroshi Ishikita, Artur Galstyan, and Ernst-Walter Knapp* Biochim. Biophys. Acta (Bioenergetics) 1767(2007) 1300-1309. doi: 10.1016/j.bbabio.2007.08.004 “Redox potential of the non-heme iron complex in bacterial photosynthetic reaction center” JournalPubmed
Frank Müh, Mohamed El-Amine Madjet, Julia Adolphs, Ayjamal, Abdurahman, Björn Rabenstein, Hiroshi Ishikita, Ernst-Walter Knapp, and Thomas Renger* Proc. Natl. Acad. Sci. U. S. A.104 (2007) 16862-16867. doi: 10.1073/pnas.0708222104 [Communicated by R. A. Marcus]”alpha-Helices direct excitation energy flow in the Fenna-Matthews-Olson protein” JournalPubmed
Sharon Hammes-Schiffer*, Elizabeth Hatcher, Hiroshi Ishikita, Jonathan Skone, and Alexander V. Soudackov Coord. Chem. Rev. 252 (2008) 384-394. doi: 10.1021/bi702151k “Theoretical studies of proton-coupled electron transfer: models and concepts relevant to bioenergetics” JournalPubmed
Hiroshi Ishikita and Arieh Warshel* Angew. Chem. 120 (2008) 709-712. doi: 10.1002/anie.200704178 Angew. Chem. Int. Ed. 47 (2008) 697-700. doi: 10.1002/anie.200704178 “Predicting drug resistant mutations of HIV protease” JournalPubmed
Hiroshi Ishikita* Biochemistry 47 (2008) 4394-4402. doi: 10.1021/bi702151k “Redox potential difference between Desulfovibrio vulgaris and Clostridium beijerinckii flavodoxins” JournalPubmed
Hiroshi Ishikita* J. Biol. Chem. 283 (2008) 30618-30623. doi: 10.1074/jbc.M803864200 “Light-induced hydrogen bonding pattern and driving force of electron transfer in AppA BLUF domain photoreceptor” JournalPubmed
Hiroshi Ishikita* FEBS Lett.584 (2010) 3464-3468. doi: 10.1016/j.febslet.2010.07.003 “Origin of the pKa shift of the catalytic lysine in acetoacetate decarboxylase” JournalPubmed
Ana Patricia Gamiz-Hernandez, Gernot Kieseritzky, Hiroshi Ishikita, and Ernst-Walter Knapp* J. Chem. Theory Comput. 7 (2011) 742-752. doi: 10.1371/journal.pone.0016920 “Rubredoxin function: redox behavior from electrostatics” JournalPubmed
Hiroshi Ishikita* PLoS One 6 (2011) e16920, 1-7. doi: 10.1371/journal.pone.0016920 “Proton-binding sites of acid-sensing ion channel 1” JournalPubmed
Hiroshi Ishikita*, Koji Hasegawa, and Takumi Noguchi Biochemistry 50 (2011) 5436-5442. doi: 10.1021/bi102023x “How does the QB site influence propagate to the QA site in Photosystem II?” JournalPubmed
Hiroshi Ishikita* PLoS One 6 (2011) e26808, 1-5. doi: 10.1371/journal.pone.0026808 “Tyrosine deprotonation and associated hydrogen bond rearrangements in a photosynthetic reaction center” JournalPubmed
Keisuke Saito, Toyokazu Ishida, Miwa Sugiura, Keisuke Kawakami, Yasufumi Umena, Nobuo Kamiya, Jian-Ren Shen, and Hiroshi Ishikita* J. Am. Chem. Soc. 133 (2011) 14379-14388. doi: 10.1021/ja203947k “Distribution of the cationic state over the chlorophyll pair of photosystem II reaction center” JournalPubmed
Keisuke Saito and Hiroshi Ishikita* Biophys. J. 101 (2011) 2018-2025. doi: 10.1016/j.bpj.2011.09.010 “Cationic state distribution over the P700 chlorophyll pair in Photosystem I” JournalPubmed
Keisuke Saito, Jian-Ren Shen, Toyokazu Ishida, and Hiroshi Ishikita* Biochemistry50 (2011) 9836-9844. doi: 10.1021/bi201366j “Short hydrogen-bond between redox-active tyrosine YZ and D1-His190 in the photosystem II crystal structure” JournalPubmed
Keisuke Saito and Hiroshi Ishikita* Proc. Natl. Acad. Sci. U. S. A.109 (2012) 167-172. doi: 10.1073/pnas.1113599108 [Direct Submission, Edited by A. Fersht] “Energetics of short hydrogen bonds in photoactive yellow protein” JournalPubmed
Keisuke Saito, Jian-Ren Shen, and Hiroshi Ishikita* Biochim. Biophys. Acta (Bioenergetics)1817 (2012) 1191-1195. doi: 10.1016/j.bbabio.2011.12.003 “Cationic state distribution over the chlorophyll d-containing PD1/PD2 pair in photosystem II” JournalPubmed
Hiroshi Ishikita*, Bryan T. Eger, Ken Okamoto, Takeshi Nishino, and Emil F. Pai J. Am. Chem. Soc. 134 (2012) 999-1009. doi: 10.1021/ja207173p “Protein conformational gating of enzymatic activity in xanthine oxidoreductase” JournalPubmed
Keisuke Saito and Hiroshi Ishikita* Biochemistry51 (2012) 1171-1177. doi: 10.1021/bi201877e “H atom positions and nuclear magnetic resonance chemical shifts of short H bonds in photoactive yellow protein” JournalPubmed
Keisuke Saito, Jian-Ren Shen, and Hiroshi Ishikita* Biophys. J. 102 (2012) 2634-2640. doi: 10.1016/j.bpj.2012.04.016 “Influence of the axial ligand on the cationic properties of the chlorophyll pair in photosystem II from Thermosynechococcus vulcanus“ JournalPubmed
Keisuke Saito, Yasufumi Umena, Keisuke Kawakami, Jian-Ren Shen, Nobuo Kamiya, and Hiroshi Ishikita* Biochemistry 51 (2012) 4290-4299. doi: 10.1021/bi300428s “Deformation of chlorin rings in the photosystem II crystal structure” JournalPubmed
Keisuke Saito, Hideki Kandori, and Hiroshi Ishikita* J. Biol. Chem. 287 (2012) 34009-34018. doi: 10.1074/jbc.M112.388348 “Factors that differentiate the H-bond strengths of water near the Schiff bases in bacteriorhodopsin and Anabaena sensory rhodopsin” JournalPubmed
Keisuke Saito and Hiroshi Ishikita* Biochim. Biophys. Acta (Bioenergetics)1827 (2013) 387-394. doi: 10.1016/j.bbabio.2012.11.009 “Formation of an unusually short hydrogen bond in photoactive yellow protein” JournalPubmed
Keisuke Saito, A. William Rutherford, and Hiroshi Ishikita* Proc. Natl. Acad. Sci. U. S. A. 110 (2013) 954-959. doi: 10.1073/pnas.1212957110 [Direct Submission, Edited by P. Joliot] “Mechanism of proton-coupled quinone reduction in Photosystem II” JournalPubmed
Keisuke Saito, A. William Rutherford, and Hiroshi Ishikita* Proc. Natl. Acad. Sci. U. S. A. 110 (2013) 7690-7695. doi: 10.1073/pnas.1300817110 [Direct Submission, Edited by H. Gray] “Mechanism of Tyrosine D oxidation in Photosystem II” JournalPubmed
Keisuke Saito and Hiroshi Ishikita* Biochim. Biophys. Acta (Bioenergetics)1837 (2014) 159-166. doi: 10.1016/j.bbabio.2013.09.013 “Influence of the Ca2+ ion on the Mn4Ca conformation and the H-bond network arrangement in Photosystem II” JournalPubmed
Hiroshi Ishikita* and Keisuke Saito J. R. Soc. Interface 11(2014) 20130518. doi: 10.1098/rsif.2013.0518 “Proton transfer reactions and hydrogen-bond networks in protein environments” JournalPubmed
Keisuke Saito, A. William Rutherford, and Hiroshi Ishikita* Nat. Commun. 6 (2015) 8488. doi: 10.1038/ncomms9488 “Energetics of proton release on the first oxidation step in the water-oxidizing enzyme” JournalPubmed
Tomohiro Takaoka, Naoki Sakashita, Keisuke Saito, and Hiroshi Ishikita* J. Phys. Chem. Lett. 7(2016) 1925-1932. doi: 10.1021/acs.jpclett.6b00656 “pKa of a proton conducting water chain in photosystem II” JournalPubmed
Keisuke Saito*, Naoki Sakashita, and Hiroshi Ishikita Aust. J. Chem. 69 (2016) 991-998. doi:10.1071/CH16248 “Energetics of the proton transfer pathway for tyrosine D in photosystem II” Journal
Kento Motoyama, Hideaki Unno, Ai Hattori, Tomohiro Takaoka, Hiroshi Ishikita, Hiroshi Kawaide, Tohru Yoshimura, and Hisashi Hemmi* J. Biol. Chem. 292 (2017) 2457-2469. doi: 10.1074/jbc.M116.752535 “A single amino acid mutation converts (R)-5-diphosphomevalonate decarboxylase into a kinase” JournalPubmed
Naoki Sakashita, Hiroshi C. Watanabe, Takuya Ikeda, and Hiroshi Ishikita* Photosynth. Res. 133 (2017) 75-85. doi: 10.1007/s11120-017-0347-1 “Structurally conserved channels in cyanobacterial and plant photosystem II” JournalPubmed
Hiroshi C. Watanabe, Yuki Yamashita, and Hiroshi Ishikita* Proc. Natl. Acad. Sci. U. S. A. 114 (2017) 2916-2921. doi: 10.1073/pnas.1617615114 [Direct Submission, Edited by A. Warshel] “Electron transfer pathways in a multi-heme cytochrome MtrF” JournalPubmed
Ryo Hasegawa, Keisuke Saito, Tomohiro Takaoka, and Hiroshi Ishikita* Photosynth. Res. 133 (2017) 297-304. doi: 10.1007/s11120-017-0382-y “pKa of ubiquinone, menaquinone, phylloquinone, plastoquinone, and rhodoquinone in aqueous solution” JournalPubmed
Keisuke Kawashima and Hiroshi Ishikita* Biochemistry 56 (2017) 3019-3028. doi: 10.1021/acs.biochem.7b00082 “Structural factors that alter the redox potential of quinones in cyanobacterial and plant photosystem I” JournalPubmed
Naoki Sakashita, Hiroshi C. Watanabe, Takuya Ikeda, Keisuke Saito, and Hiroshi Ishikita* Biochemistry 56 (2017) 3049-3057. doi: 10.1021/acs.biochem.7b00220 “Origins of water molecules in the photosystem II crystal structure” JournalPubmed
Takuya Ikeda, Keisuke Saito, Ryo Hasegawa, and Hiroshi Ishikita* Angew. Chem. 129 (2017) 9279-9282. doi: 10.1002/ange.201705512 Angew. Chem. Int. Ed. 56 (2017) 9151-9154. doi: 10.1002/anie.201705512 “Existence of isolated H3O+ in the protein interior” JournalPubmed
Hiroshi C. Watanabe*, Maximilian Kubillus, Tomas Kubar, Robert Stach, Boris Mizaikoff, and Hiroshi Ishikita Phys. Chem. Chem. Phys. 19 (2017) 17985-17997. doi: 10.1039/C7CP01708A “Cation solvation with quantum chemical effects modeled by size-consistent multi-partitioning quantum mechanics/molecular mechanics method” JournalPubmed
Shinnosuke Kishi, Keisuke Saito, Yuki Kato, and Hiroshi Ishikita* Photosynth. Res. 134 (2017) 193-200. doi: 10.1007/s11120-017-0433-4 “Redox potentials of ubiquinone, menaquinone, phylloquinone, and plastoquinone in aqueous solution” JournalPubmed
Hiroshi C. Watanabe, Yuki Yamashita, and Hiroshi Ishikita* Proc. Natl. Acad. Sci. U. S. A. 114 (2017) E10029-E10030. doi: 10.1073/pnas.1717048114 “Molecular dynamics simulations do not provide functionally relevant values of redox potential in MtrF” JournalPubmed
Keisuke Saito*, Takumi Suzuki, and Hiroshi Ishikita J. Photochem. Photobiol. A 358 (2018) 422-431. doi: 10.1016/j.jphotochem.2017.10.003 “Absorption-energy calculations of chlorophyll a and b with an explicit solvent model” Journal
Keisuke Kawashima, Tomohiro Takaoka, Hiroki Kimura, Keisuke Saito, and Hiroshi Ishikita* Nat. Commun. 9 (2018) 1247. doi: 10.1038/s41467-018-03545-w “O2 evolution and recovery of the water-oxidizing enzyme” JournalPubmed
Keisuke Kawashima and Hiroshi Ishikita* Chem. Sci. 9 (2018) 4083-4092. doi 10.1039/C8SC00424B “Energetic insights into two electron transfer pathways in light-driven energy-converting enzymes” JournalPubmed
Yoshitaka Saga*, Keiya Hirota, Sayaka Matsui, Hitoshi Asakawa, Hiroshi Ishikita, and Keisuke Saito* Biochemistry 57 (2018) 3075-3083. doi: 10.1021/acs.biochem.8b00259 “Selective removal of B800 bacteriochlorophyll a from the light-harvesting complex 2 of the purple photosynthetic bacterium Phaeospirillum molischianum” JournalPubmed
Keisuke Kawashima, Keisuke Saito, and Hiroshi Ishikita* Biochemistry 57 (2018) 4997-5004. doi: 10.1021/acs.biochem.8b00574 “Mechanism of radical formation in the H-bond network of D1-Asn298 in photosystem II” JournalPubmed
Keiichi Kojima, Hiroshi C. Watanabe, Satoko Doi, Natsuki Miyoshi, Misaki Kato, Hiroshi Ishikita, Yuki Sudo* Biophys. Physicobiol. 15 (2018) 179-188. doi: 10.2142/biophysico.15.0_179 “Mutational analysis of the conserved carboxylates of anion channelrhodopsin-2 (ACR2) expressed in Escherichia coli and their roles in anion transport” JournalPubmed
Keisuke Saito and Hiroshi Ishikita* Biochim. Biophys. Acta (Bioenergetics) 1860 (2019) 148059. doi: 10.1016/j.bbabio.2019.148059 “Mechanism of protonation of the over-reduced Mn4CaO5 cluster in photosystem II” JournalPubmed
Hiroyuki Tamura*, Koki Azumaya, and Hiroshi Ishikita J. Phys. Chem. Lett. 10 (2019) 7623-7628. doi: 10.1021/acs.jpclett.9b03029 “Long-range exciton diffusion via singlet revival mechanism” JournalPubmed
Keiichi Kojima, Tetsuya Ueta, Tomoyasu Noji, Keisuke Saito, Kanae Kanehara, Susumu Yoshizawa, Hiroshi Ishikita, Yuki Sudo* Sci. Rep. 10 (2020) 282. doi: 10.1038/s41598-019-57122-2 “Vectorial proton transport mechanism of RxR, a phylogenetically distinct and thermally stable microbial rhodopsin” JournalPubmed
Manoj Mandal, Keisuke Kawashima, Keisuke Saito, and Hiroshi Ishikita* J. Phys. Chem. Lett. 11 (2020) 249-255. doi: 10.1021/acs.jpclett.9b02831 “Redox potential of the oxygen-evolving complex in the electron transfer cascade of photosystem II” JournalPubmed
Hiroyuki Tamura* and Hiroshi Ishikita J. Phys. Chem. A 124 (2020) 5081-5088. doi: 10.1021/acs.jpca.0c02228 “Quenching of singlet oxygen by carotenoids via ultrafast super-exchange dynamics” JournalPubmed
Hiroyuki Tamura, Keisuke Saito, and Hiroshi Ishikita* Proc. Natl. Acad. Sci. U. S. A. 117 (2020) 6373-6382. doi: 10.1073/pnas.2000895117 [Direct Submission, Edited by P. Falkowski] “Acquirement of water-splitting ability and alteration of charge-separation mechanism in photosynthetic reaction centers” JournalPubmed
Naoki Sakashita, Hiroshi Ishikita, and Keisuke Saito* Phys. Chem. Chem. Phys. 22 (2020) 15831-15841. doi: 10.1039/d0cp00295j “Rigidly hydrogen-bonded water molecules facilitate proton transfer in photosystem II” JournalPubmed
Keisuke Saito, Minesato Nakagawa, and Hiroshi Ishikita* Commun. Chem. 3 (2020) 89. doi: 10.1038/s42004-020-00336-7 “pKa of the ligand water molecules in the oxygen-evolving Mn4CaO5 cluster in photosystem II” Journal
Keisuke Saito, Manoj Mandal, and Hiroshi Ishikita* Biochemistry 59 (2020) 3216-3224. doi: 10.1021/acs.biochem.0c00177 “Energetics of ionized water molecules in the H-bond network near the Ca2+ and Cl– binding sites in photosystem II” JournalPubmed
Keiichi Kojima, Natsuki Miyoshi, Atsushi Shibukawa, Srikanta Chowdhury, Masaki Tsujimura, Tomoyasu Noji, Hiroshi Ishikita, Akihiro Yamanaka, and Yuki Sudo* J. Phys. Chem. Lett. 11 (2020) 6214-6218. doi: 10.1021/acs.jpclett.0c01406 “Green-sensitive, long-lived, step-functional anion channelrhodopsin-2 variant as a high-potential neural silencing tool” JournalPubmed
Keisuke Saito*, Koji Mitsuhashi, and Hiroshi Ishikita* J. Photochem. Photobiol. A 402 (2020) 112799. doi: 10.1016/j.jphotochem.2020.112799 “Dependence of the chlorophyll wavelength on the orientation of a charged group: why does the accessory chlorophyll have a low site energy in photosystem II?” Journal
Keisuke Saito, Manoj Mandal, and Hiroshi Ishikita* Phys. Chem. Chem. Phys. 22 (2020) 25467-25473. doi: 10.1039/D0CP04265J “Redox potentials along the redox-active low-barrier H-bonds in electron transfer pathways” JournalPubmed
Manoj Mandal, Keisuke Saito, and Hiroshi Ishikita* J. Phys. Chem. Lett. 11 (2020) 10262-10268. doi: 10.1021/acs.jpclett.0c02868 “The nature of the short oxygen-oxygen distance in the Mn4CaO6 complex of the photosystem II crystals” JournalPubmed
Masaki Tsujimura and Hiroshi Ishikita* J. Phys. Chem. B 124 (2020) 11819-11826. doi: 10.1021/acs.jpcb.0c08910 “Insights into the protein functions and absorption wavelengths of microbial rhodopsins” JournalPubmed
Masaki Tsujimura, Tomoyasu Noji, Keisuke Saito, Keiichi Kojima, Yuki Sudo, and Hiroshi Ishikita* Biochim. Biophys. Acta (Bioenergetics)1862(2021) 148349. doi: 10.1016/j.bbabio.2020.148349 “Mechanism of absorption wavelength shifts in anion channelrhodopsin-1 mutants” JournalPubmed
Hiroshi Kuroda1, Keisuke Kawashima1, Kazuyo Ueda, Takuya Ikeda, Keisuke Saito, Ryo Ninomiya, Chisato Hida, Yuichiro Takahashi*, Hiroshi Ishikita* Biochim. Biophys. Acta (Bioenergetics)1862 (2021) 148329. doi: 10.1016/j.bbabio.2020.148329 “Proton transfer pathway from the oxygen-evolving complex in photosystem II substantiated by extensive mutagenesis” 1These authors contributed equally to this work. JournalPubmed
Masaki Tsujimura* and Hiroshi Ishikita* J. Biol. Chem. 296 (2021) 100459. doi: 10.1016/j.jbc.2021.100459 “Identification of intermediate conformations in the photocycle of the light-driven sodium-pumping rhodopsin KR2” JournalPubmed
Koji Mitsuhashi, Hiroyuki Tamura, Keisuke Saito, and Hiroshi Ishikita* J. Phys. Chem. B 125 (2021) 2879-2885. doi: 10.1021/acs.jpcb.0c10885 “Nature of asymmetric electron transfer in the symmetric pathways of photosystem I” JournalPubmed
Manoj Mandal, Keisuke Saito, and Hiroshi Ishikita* J. Phys. Chem. Lett. 12 (2021) 4032-4037. doi: 10.1021/acs.jpclett.1c00814 “Two distinct oxygen-radical conformations in the X‑ray free electron laser structures of photosystem II” JournalPubmed
Hiroyuki Tamura*, Keisuke Saito, and Hiroshi Ishikita Chem. Sci. 12 (2021) 8131-8140. doi: 10.1039/D1SC01497H “The origin of unidirectional charge separation in photosynthetic reaction centers: nonadiabatic quantum dynamics of exciton and charge in the pigment-protein complexes” JournalPubmed
Keisuke Saito*, Minesato Nakagawa, Manoj Mandal, and Hiroshi Ishikita* Photosynth. Res. 148 (2021) 153-159. doi: 10.1007/s11120-021-00846-y “Role of redox-inactive metals in controlling the redox potential of heterometallic manganese-oxido clusters” JournalPubmed
Yu Sugo, Keisuke Saito, and Hiroshi Ishikita* Proc. Natl. Acad. Sci. U. S. A. 118 (2021) e2103203118. doi: 10.1073/pnas.2103203118 “Mechanism of the formation of proton transfer pathways in photosynthetic reaction centers” JournalPubmed
Tomoki Kanda1, Keisuke Saito1, and Hiroshi Ishikita* J. Phys. Chem. Lett. 12 (2021) 7431-7438. doi: 10.1021/acs.jpclett.1c01896 “Electron acceptor-donor Fe sites in the iron-sulfur cluster of photosynthetic electron-transfer pathways” 1These authors contributed equally to this work. JournalPubmed
Yasunori Saitoh1, Namiki Mitani-Ueno1, Keisuke Saito1, Kengo Matsuki, Sheng Huang, Lingli Yang, Naoki Yamaji, Hiroshi Ishikita, Jian-Ren Shen, Jian Feng Ma, and Michihiro Suga* Nat. Commun. 12 (2021) 6236. doi: 10.1038/s41467-021-26535-x “Structural basis for high selectivity of a rice silicon channel Lsi1” 1These authors contributed equally to this work. JournalPubmed
Taichi Tsuneishi1, Masataka Takahashi1, Masaki Tsujimura1, Keiichi Kojima, Hiroshi Ishikita, Yasuo Takeuchi, and Yuki Sudo* Front. Mol. Biosci. 8 (2021) 794948. doi: 10.3389/fmolb.2021.794948 “Exploring the retinal binding cavity of archaerhodopsin-3 by replacing the retinal chromophore with a dimethyl phenylated derivative” 1These authors contributed equally to this work. JournalPubmed
Masaki Tsujimura1, Keiichi Kojima1, Shiho Kawanishi, Yuki Sudo*, and Hiroshi Ishikita* eLife 10 (2021) e72264. doi: 10.7554/eLife.72264 “Proton transfer pathway in anion channelrhodopsin-1” 1These authors contributed equally to this work. JournalPubmed
Hiroyuki Tamura*, Keisuke Saito, and Hiroshi Ishikita J. Phys. Chem. B 125 (2021) 13460-13466. doi: 10.1021/acs.jpcb.1c09538 “Long-range electron tunneling from the primary to secondary quinones in photosystem II enhanced by hydrogen bonds with non-heme Fe complex” JournalPubmed
Manoj Mandal, Keisuke Saito, and Hiroshi Ishikita* J. Phys. Chem. B 126 (2022) 123-131. doi: 10.1021/acs.jpcb.1c09176 “Requirement of chloride for downhill electron transfer pathway from the water-splitting center in natural photosynthesis” JournalPubmed
Yutaro Saito, Hiroyuki Yatabe, Iori Tamura, Yohei Kondo, Ryo Ishida, Tomohiro Seki, Keita Hiraga, Akihiro Eguchi, Yoichi Takakusagi, Keisuke Saito, Hiroshi Ishikita, Kazutoshi Yamamoto, Murali C. Krishna*, and Shinsuke Sando* Sci. Adv. 8 (2022) eabj2667. doi: 10.1126/sciadv.abj2667 “Structure-guided design enables development of a hyperpolarized molecular probe for the detection of aminopeptidase N activity in vivo” JournalPubmed
Manoj Mandal, Keisuke Saito, and Hiroshi Ishikita* J. Phys. Soc. Jpn.91 (2022) 091012. doi: 10.7566/JPSJ.91.091012 “Release of electrons and protons from substrate water molecules at the oxygen-evolving complex in photosystem II” Journal
Tomoki Kanda, Keisuke Saito, and Hiroshi Ishikita* J. Phys. Chem. B 126 (2022) 3059-3066. doi: 10.1021/acs.jpcb.2c01320 “Mechanism of mixed-valence Fe2.5+…Fe2.5+ formation in Fe4S4 clusters in the ferredoxin binding motif” JournalPubmed
Manoj Mandal, Keisuke Saito, and Hiroshi Ishikita* ACS Phys. Chem Au2 (2022) 423-429. doi: 10.1021/acsphyschemau.2c00019 “Release of the proton and formation of the low-barrier hydrogen bond between tyrosine D and D2-His189 in photosystem II” JournalPubmed
Keisuke Saito*, Tianyang Xu, and Hiroshi Ishikita* J. Phys. Chem. B 126 (2022) 4999-5006. doi: 10.1021/acs.jpcb.2c02193 “Correlation between C=O stretching vibrational frequency and pKa shift of carboxylic acids” JournalPubmed
Yu Sugo, Keisuke Saito, and Hiroshi Ishikita* Biochemistry 61 (2022) 1836-1843.doi: 10.1021/acs.biochem.2c00324 “Conformational changes and H-bond rearrangements during quinone release in photosystem II” JournalPubmed
Ko Imaizumi, Taishi Nishimura, Ryo Nagao, Keisuke Saito, Takeshi Nakano, Hiroshi Ishikita, Takumi Noguchi, and Kentaro Ifuku* PNAS Nexus1 (2022) pgac136. doi: 10.1093/pnasnexus/pgac136 “D139N mutation of PsbP enhances the oxygen-evolving activity of photosystem II through stabilized binding of a chloride ion” JournalPubmed
Hiroyuki Tamura*, Hiroki Takezawa, Makoto Fujita, and Hiroshi Ishikita* Phys. Chem. Chem. Phys. 24 (2022) 21367-21371. doi: 10.1039/D2CP03126D “Self-assembled coordination cage enhances reactivity of confined amides via mechanical bond-twisting” JournalPubmed
Yu Sugo and Hiroshi Ishikita* Front. Plant Sci. 13 (2022) 934736. doi: 10.3389/fpls.2022.934736 “Proton-mediated photoprotection mechanism in photosystem II” JournalPubmed
Keisuke Saito*, Hiroyuki Mino, Shunya Nishio, and Hiroshi Ishikita* PNAS Nexus 1(2022) pgac221. doi: 10.1093/pnasnexus/pgac221 “Protonation structure of the closed-cubane conformation of the O2-evolving complex in photosystem II” JournalPubmed
Tomoki Kanda and Hiroshi Ishikita* Biochemistry 61 (2022) 2621-2627. doi: 10.1021/acs.biochem.2c00524 “Energetics of the electron transfer pathways in the homodimeric photosynthetic reaction center” JournalPubmed
Tomoyasu Noji* and Hiroshi Ishikita J. Phys. Chem. B 126 (2022) 9945-9955. doi: 10.1021/acs.jpcb.2c04359 “Mechanism of absorption wavelength shift of bacteriorhodopsin during photocycle” JournalPubmed
Yu Sugo, Hiroyuki Tamura, and Hiroshi Ishikita* J. Phys. Chem. B 126(2022) 9549-9558. doi: 10.1021/acs.jpcb.2c05713 “Electron transfer route between quinones in type-II reaction centers” JournalPubmed
Masaki Tsujimura*, Yoshihiro Chiba, Keisuke Saito, and Hiroshi Ishikita* Commun. Biol. 5 (2022) 1336. doi: 10.1038/s42003-022-04311-x “Proton transfer and conformational changes along the hydrogen bond network in heliorhodopsin” JournalPubmed
Sho Koyasu, Shoichiro Horita, Keisuke Saito, Minoru Kobayashi, Hiroshi Ishikita, Christalle C.T. Chow, Gouki Kambe, Shigeto Nishikawa, Toshi Menju, Akiyo Morinibu, Yasushi Okochi, Yoshiaki Tabuchi, Yasuhito Onodera, Norihiko Takeda, Hiroshi Date, Gregg L. Semenza, Ester M. Hammond, and Hiroshi Harada* EMBO rep. 24 (2023) e54042. doi: 10.15252/embr.202154042 “ZBTB2 links p53-deficiency to HIF-1-mediated hypoxia signaling for cancer aggressiveness” JournalPubmed
Hiroyuki Tamura*, Keisuke Saito, Shunya Nishio, and Hiroshi Ishikita* J. Phys. Chem. B127 (2023) 205-211. doi: 10.1021/acs.jpcb.2c08246 “Electron-transfer route in the early oxidation states of the Mn4CaO5 cluster in photosystem II” JournalPubmed
Masaki Tsujimura*, Minaka Sugano, Hiroshi Ishikita, and Keisuke Saito* J. Phys. Chem. B127 (2023) 505-513. doi: 10.1021/acs.jpcb.2c07232 “Mechanism of absorption wavelength shift depending on the protonation state of the acrylate group in chlorophyll c” JournalPubmed
Keisuke Saito*, Koji Mitsuhashi, Hiroyuki Tamura*, and Hiroshi Ishikita* Biophys. J. 22 (2023) 470-483. doi: 10.1016/j.bpj.2023.01.002 “Quantum mechanical analysis of excitation energy transfer couplings in photosystem II” JournalPubmed
Tomoki Kanda and Hiroshi Ishikita* Biochemistry 62 (2023) 934-941. doi: 10.1021/acs.biochem.2c00689 “Energetic diversity in the electron transfer pathways of type I photosynthetic reaction centers” JournalPubmed
Manoj Mandal*, Keisuke Saito, and Hiroshi Ishikita* Phys. Chem. Chem. Phys. 25 (2023) 6473-6480. doi: 10.1039/D2CP05036F “Substitution of Ca2+ and changes in the H-bond network near the oxygen-evolving complex of photosystem II” JournalPubmed
Keisuke Saito*, Shu Nakao, and Hiroshi Ishikita* Front. Plant Sci. 14 (2023)1029674. doi: 10.3389/fpls.2023.1029674 “Identification of the protonation and oxidation states of the oxygen-evolving complex in the low-dose X-ray crystal structure of photosystem II” JournalPubmed
Yu Sugo and Hiroshi Ishikita* Biochemistry 62 (2023) 1544-1552. doi: 10.1021/acs.biochem.3c00013 “Mechanism of asparagine-mediated proton transfer in photosynthetic reaction centers” JournalPubmed
Tomoki Kanda and Hiroshi Ishikita* J. Phys. Chem. B 127 (2023) 4998-5004. doi: 10.1021/acs.jpcb.3c01071 “Redox potentials of iron-sulfur clusters in type I photosynthetic reaction centers” JournalPubmed
Yoshihiro Chiba, Masaki Tsujimura, Keisuke Saito, and Hiroshi Ishikita* Biochemistry 62 (2023) 2363–2370, doi: 10.1021/acs.biochem.3c00193 “pH-dependent binding and releasing mechanism of acetate in the inner water cavity of heliorhodopsin” Journal
Masahiro Saito, Keisuke Saito, and Hiroshi Ishikita* iScience 26 (2023) 107352. doi: 10.1016/j.isci.2023.107352 “Structural and energetic insights into Mn-to-Fe substitution in the oxygen-evolving complex” Journalpubmed
Keisuke Saito*, Shunya Nishio, Mizue Asada, Hiroyuki Mino, and Hiroshi Ishikita* PNAS Nexus 2 (2023) pgad244. doi: 10.1093/pnasnexus/pgad244 “Insights into the protonation state and spin structure for the g=2 multiline EPR signal of the oxygen-evolving complex” JournalPubmed
Gai Nishikawa, Yu Sugo, Keisuke Saito, and Hiroshi Ishikita* eLife12 (2023) e88955. doi: 10.7554/eLife.88955 “Absence of electron transfer-associated changes in the time-dependent X-ray free-electron laser structures of the photosynthetic reaction center” JournalPubmed
Masaki Tsujimura*, Keisuke Saito, and Hiroshi Ishikita* Biophys. J. 122 (2023) 4336-4347. doi: 10.1016/j.bpj.2023.10.012 “Stretching vibrational frequencies and pKa differences in H-bond networks of protein environments” JournalPubmed
Tomoyasu Noji, Hiroyuki Tamura, Hiroshi Ishikita, and Keisuke Saito* J. Phys. Chem. B 127 (2023) 10351-10359. doi: 10.1021/acs.jpcb.3c06483 “Difference in the charge-separation energetics between distinct conformers in the PixD photoreceptor” JournalPubmed
Yusuke Kato, Hiroshi Kuroda, Shin-Ichiro Ozawa, Keisuke Saito, Vivek Dogra, Martin Scholz, Guoxian Zhang, Catherine de Vitry, Hiroshi Ishikita, Chanhong Kim, Michael Hippler, Yuichiro Takahashi, and Wataru Sakamoto eLife12 (2023) RP88822. doi:10.7554/eLife.88822 “Characterization of tryptophan oxidation affecting D1 degradation by FtsH in the photosystem II quality control of chloroplasts” JournalPubmed
Keisuke Saito*, Shunya Nishio, and Hiroshi Ishikita* PNAS Nexus2 (2023) pgad423. doi: 10.1093/pnasnexus/pgad423 “Interplay of two low-barrier hydrogen bonds in long-distance proton-coupled electron transfer for water oxidation” JournalPubmed
Gai Nishikawa, Keisuke Saito, and Hiroshi Ishikita* Biochemistry 63 (2024) 1206-1213. doi: 10.1021/acs.biochem.4c00010 “Modulation of electron transfer branches by atrazine and triazine herbicides in photosynthetic reaction centers” JournalPubmed
Keisuke Saito, Yang Chen, and Hiroshi Ishikita* J. Phys. Chem. B 128(2024) 4728-4734. doi: 10.1021/acs.jpcb.4c01997 “Exploring the deprotonation process during incorporation of a ligand water molecule at the dangling Mn site in photosystem II” JournalPubmed
Tomoyasu Noji, Yoshihiro Chiba, Keisuke Saito, and Hiroshi Ishikita* Biochemistry 63 (2024) 1505-1512. doi: 10.1021/acs.biochem.4c00182 “Energetics of the H-bond network in Exiguobacterium sibiricum rhodopsin” JournalPubmed
Hiroyuki Tamura, Takahiro Nakama, Anouk Rossen, Hiroshi Ishikita, and Makoto Fujita* Chem. Lett. 53(2024) upae101. doi: 10.1093/chemle/upae101 “Organic solvent-induced structural changes in a protein confined in a giant coordination cage” Journal
Takayuki Nagae, Mitsuhiro Takeda, Tomoyasu Noji, Keisuke Saito, Hiroshi Aoyama, Yohei Miyanoiri, Yutaka Ito, Masatsune Kainosho, Yuu Hirose, Hiroshi Ishikita*, Masaki Mishima*. Proc. Natl. Acad. Sci. U. S. A. 121 (2024) e2404472121. doi: 10.1073/pnas.2404472121 “Direct evidence for a deprotonated lysine serving as a “H-bond acceptor” in a photoreceptor protein” JournalPubmed
Tomoyasu Noji, Keisuke Saito, and Hiroshi Ishikita* Biophys. J. 123 (2024) 3375-3385. doi: 10.1016/j.bpj.2024.08.001 “Molecular origins of absorption wavelength variation among phycocyanobilin-binding proteins” JournalPubmed
Tomoyasu Noji, Keisuke Saito, and Hiroshi Ishikita* Commun. Chem. 7 (2024) 192. doi: 10.1038/s42004-024-01281-5 “Absence of a link between stabilized charge-separated state and structural changes proposed from crystal structures of a photosynthetic reaction center” JournalPubmed
Gouki Kambe, Minoru Kobayashi, Hiroshi Ishikita, Sho Koyasu, Ester M. Hammond, Hiroshi Harada* Biochem. Biophys. Res. Commun. 733 (2024) 150604. doi: 10.1016/j.bbrc.2024.150604 “ZBTB7A forms a heterodimer with ZBTB2 and inhibits ZBTB2 homodimerization required for full activation of HIF-1” JournalPubmed
Keisuke Saito*, Hiroyuki Tamura, and Hiroshi Ishikita* J. Phys. Chem. Lett. 15 (2024) 9183-9192. doi: 10.1021/acs.jpclett.4c02232 “Superexchange electron transfer and protein matrix in the charge-separation process of photosynthetic reaction centers” JournalPubmed
Ruri Nihara, Keisuke Saito, Hiroshi Kuroda, Yasuto Komatsu, Yang Chen, Hiroshi Ishikita*, and Yuichiro Takahashi* Biochim. Biophys. Acta (Bioenergetics) 1866 (2024)149507. doi: 10.1016/j.bbabio.2024.149507 “D1-Tyr246 and D2-Tyr244 in photosystem II: Insights into bicarbonate binding and electron transfer from QA•− to QB” JournalPubmed
David C. Calianese1, Tomoyasu Noji1, Jennifer A. Sullivan, Kelly Schoch, Vandana Shashi, Vanda McNiven, Luiza Lorena Pires Ramos, Albena Jordanova, Judit Kárteszi, Hiroshi Ishikita, and Shigekazu Nagata* Proc. Natl. Acad. Sci. U. S. A. 121 (2024) e2415755121. doi: 10.1073/pnas.2415755121 “Substrate specificity controlled by the exit site of human P4-ATPases, revealed by de novo point mutations in neurological disorders” 1These authors contributed equally to this work. JournalPubmed
Tomoyasu Noji, Keisuke Saito, and Hiroshi Ishikita* Biochemistry 64 (2025) 203-212. doi: 10.1021/acs.biochem.4c00521 “How the electron-transfer cascade is maintained in chlorophyll-d containing photosystem I” JournalPubmed
Masaki Nakama1, Tomoyasu Noji1, Keiichi Kojima1, Susumu Yoshizawa, Hiroshi Ishikita, and Yuki Sudo* J. Biol. Chem. 301 (2025) 108334. doi: 10.1016/j.jbc.2025.108334 “Roles of basic amino acid residues in substrate binding and transport of the light-driven anion pump Synechocystis halorhodopsin (SyHR)” 1These authors contributed equally to this work. JournalPubmed
Mai Kugawa, Kouki Kawakami, Ryoji Kise, Carl-Mikael Suomivuori, Masaki Tsujimura, Kazuhiro Kobayashi, Asato Kojima, Wakana J. Inoue, Masahiro Fukuda, Toshiki E. Matsui, Ayami Fukunaga, Junki Koyanagi, Suhyang Kim, Hisako Ikeda, Keitaro Yamashita, Keisuke Saito, Hiroshi Ishikita, Ron O. Dror, Asuka Inoue, and Hideaki E. Kato* Nat. Commun. 16(2025) 2809. doi: 10.1038/s41467-025-57983-4 “Structural insights into lipid chain-length selectivity and allosteric activation/inactivation mechanism of FFA2” JournalPubmed
Hiroshi Ishikita* and Keisuke Saito Biochemistry 64 (2025) 1895-1906. doi: 10.1021/acs.biochem.5c00112 “Photosystem II: Probing protons and breaking barriers” JournalPubmed
Masaki Tsujimura*, Hiroshi Ishikita, and Keisuke Saito* Phys. Chem. Chem. Phys. 27(2025)9794-9805. doi; 10.1039/d5cp00511f “Determinants of hydrogen bond distances in proteins” JournalPubmed
Keisuke Saito*, Makiko Kosugi, Linhao Qiu, Jun Minagawa, and Hiroshi Ishikita* J. Biol. Chem. 301 (2025) 108518. doi: 10.1016/j.jbc.2025.108518 “Identification and design principles of far-red-absorbing chlorophyll in the light-harvesting complex” JournalPubmed
Hiroyuki Tamura*, Keisuke Saito, and Hiroshi Ishikita* ACS Omega (2025) doi: 10.1021/acsomega.5c00945 “Electron transfer mechanism from the oxygen-evolving complex to the electron-acceptor tyrosine during the S2 to S3 transition in photosystem II” JournalPubmed
Irina Karyagina1, Yulia Pushkar, Dietmar Stehlik, Art van der Groot, Hiroshi Ishikita, Ernst-Walter Knapp, Bharat Jagannathan, Rufat Agalarov, and John H. Golbeck* Photosynthesis. Energy from the Sun (2008) pp. 101-104 (DOI: 10.1007/978-1-4020-6709-9_23) “The influence of aspartate 575PsaB on the midpoint potentials of phylloquinones A1A/A1B and the Fx iron-sulfur cluster in photosystem I”
Keisuke Saito and Hiroshi Ishikita* Nature Precedings (2011) doi:10.1038/npre.2011.6486.1 “Cationic state distributions over chlorophyll pairs in photosystem I and II”
