Bicarbonate-Mediated CO₂ Formation on Both Sides of Photosystem II.

ABSTRACT: The effect of bicarbonate (HCO₃^-) on photosystem II (PSII) activity was discovered in the 1950s, but only recently have its molecular mechanisms begun to be clarified. Two chemical mechanisms have been proposed. One is for the electron-donor side, in which mobile HCO₃^- enhances and possibly regulates water oxidation by acting as proton acceptor, after which it dissociates into CO₂ and H₂O. The other is for the electron-acceptor side, in which (i) reduction of the Q_A quinone leads to the release of HCO₃^- from its binding site on the non-heme iron and (ii) the E_m potential of the Q_A/Q_A^•- couple increases when HCO₃^- dissoci

SUBMITTER: Shevela D 

PROVIDER: S-EPMC7467574 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature