Identification of a Na+-Binding Site near the Oxygen-Evolving Complex of Spinach Photosystem II

Jimin Wang, Joshua M. Perez-Cruet, Hao Li Huang, Krystle Reiss, Christopher J. Gisriel, Gourab Banerjee, Divya Kaur, Ipsita Ghosh, Alisha Dziarski, M. R. Gunner, Victor S. Batista, Gary W. Brudvig

Research output: Contribution to journalArticlepeer-review

Abstract

The oxygen-evolving complex (OEC) of photosystem II (PSII) is an oxomanganese cluster composed of four redox-active Mn ions and one redox-inactive Ca2+ ion, with two nearby bound Cl- ions. Sodium is a common counterion of both chloride and hydroxide anions, and a sodium-specific binding site has not been identified near the OEC. Here, we find that the oxygen-evolution activity of spinach PSII increases with Na+ concentration, particularly at high pH. A Na+-specific binding site next to the OEC, becomes available after deprotonation of the D1-H337 amino acid residue, is suggested by the analysis of two recently published PSII cryo-electron microscopy maps in combination with quantum mechanical calculations and multiconformation continuum electrostatics simulations.

Original languageEnglish
Pages (from-to)2823-2831
Number of pages9
JournalBiochemistry
Volume59
Issue number30
DOIs
Publication statusPublished - Aug 4 2020

ASJC Scopus subject areas

  • Biochemistry

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