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Structural basis of redox modulation on chloroplast ATP synthase.

ABSTRACT: In higher plants, chloroplast ATP synthase has a unique redox switch on its ? subunit that modulates enzyme activity to limit ATP hydrolysis at night. To understand the molecular details of the redox modulation, we used single-particle cryo-EM to determine the structures of spinach chloroplast ATP synthase in both reduced and oxidized states. The disulfide linkage of the oxidized ? subunit introduces a torsional constraint to stabilize the two ? hairpin structures. Once reduced, free cysteines alleviate this constraint, resulting in a concerted motion of the enzyme complex and a smooth transition between rotary states to facilitate the ATP synthesis. We added an uncompetitive inhibitor, tentoxin, in the reduced sample to limit the flexibility of the enzyme and obtained high-resolution details. Our cryo-EM structures provide mechanistic insight into the redox modulation of the energy regulation activity of chloroplast ATP synthase.

SUBMITTER: Yang JH

PROVIDER: S-EPMC7468127 | biostudies-literature | 2020 Sep

REPOSITORIES: biostudies-literature

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Structural basis of redox modulation on chloroplast ATP synthase.

Yang Jay-How JH Williams Dewight D Kandiah Eaazhisai E Fromme Petra P Chiu Po-Lin PL

Communications biology 20200902 1

In higher plants, chloroplast ATP synthase has a unique redox switch on its γ subunit that modulates enzyme activity to limit ATP hydrolysis at night. To understand the molecular details of the redox modulation, we used single-particle cryo-EM to determine the structures of spinach chloroplast ATP synthase in both reduced and oxidized states. The disulfide linkage of the oxidized γ subunit introduces a torsional constraint to stabilize the two β hairpin structures. Once reduced, free cysteines a ...[more]

PMID: 32879423

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