[pH-dependent regulation of electron transport in chloroplasts. Computer simulation investigation]

Abstract

A mathematical model for the description of the key stages of photosynthetic electron transport and transmembrane proton transfer in chloroplasts is presented. Numerical modeling of electron and proton transport with due regard for regulatory processes on the donor and acceptor sites of photosystem I (PS I) was performed. The influence of pH-dependent activation of the Calvin cycle enzymes and energy dissipation in PS II (nonphotochemical quenching of chlorophyll fluorescence) on the kinetics of light-reduced redox transients of P700, plastoquinone and NADPH, as well as intrathylakoid pH(in), and ATP was studied. It was demonstrated that pH-dependent regulatory processes influence the distribution of electron fluxes on the acceptor site of PS I and the total rate of electron flow between PS II and PS I. The light-induced activation of the Calvin cycle enzymes leads to a significant acceleration of the electron flow to NADP+ and the reduction of the electron flow from PS 1 to molecular oxygen.