D1-S169A Substitution of Photosystem II Perturbs Water Oxidation

Ipsita Ghosh, Gourab Banerjee, Christopher J. Kim, Krystle Reiss, Victor S. Batista, Richard J. Debus, Gary W Brudvig

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Abstract

In photosystem II (PSII), photosynthetic water oxidation occurs at the tetramanganese-calcium cluster that cycles through light-induced intermediates (S 0 -S 4 ) to produce oxygen from two substrate waters. The surrounding hydrogen-bonded amino acid residues and waters form channels that facilitate proton transfer and substrate water delivery, thereby ensuring efficient water oxidation. The residue D1-S169 lies in the "narrow" channel and forms hydrogen bonds with the Mn 4 CaO 5 cluster via waters W1 and Wx. To probe the role of the narrow channel in substrate-water binding, we studied the D1-S169A mutation. PSII core complexes isolated from mutant cells exhibit inefficient S-state cycling and delayed oxygen evolution. The S 2 -state multiline EPR spectrum of D1-S169A PSII core complexes differed significantly from that of wild-type, and FTIR difference spectra showed that the mutation strongly perturbs the extensive network of hydrogen bonds that extends at least from D1-Y161 (Y Z ) to D1-D61. These results imply a possible role of D1-S169 in proton egress or substrate water delivery.

Original languageEnglish
Pages (from-to)1379-1387
Number of pages9
JournalBiochemistry
Volume58
Issue number10
DOIs
Publication statusPublished - Mar 12 2019

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ASJC Scopus subject areas

  • Biochemistry

Cite this

Ghosh, I., Banerjee, G., Kim, C. J., Reiss, K., Batista, V. S., Debus, R. J., & Brudvig, G. W. (2019). D1-S169A Substitution of Photosystem II Perturbs Water Oxidation. Biochemistry, 58(10), 1379-1387. https://doi.org/10.1021/acs.biochem.8b01184