Chloroplast ATP Synthase Modulation of the Thylakoid Proton Motive Force: Implications for Photosystem I and Photosystem II Photoprotection.

ABSTRACT: In wild type plants, decreasing CO₂ lowers the activity of the chloroplast ATP synthase, slowing proton efflux from the thylakoid lumen resulting in buildup of thylakoid proton motive force (pmf). The resulting acidification of the lumen regulates both light harvesting, via the q_E mechanism, and photosynthetic electron transfer through the cytochrome b₆f complex. Here, we show that the cfq mutant of Arabidopsis, harboring single point mutation in its γ-subunit of the chloroplast ATP synthase, increases the specific activity of the ATP synthase and disables its down-regulation under low CO₂. The increased thylakoid proton conductivity (g_H⁺) in cfq results in decreased pmf and lumen acidifica

SUBMITTER: Kanazawa A 

PROVIDER: S-EPMC5413553 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature