Unexpected Heme Redox Potential Values Implicate an Uphill Step in Cytochrome b₆f.

ABSTRACT: Cytochromes bc, key enzymes of respiration and photosynthesis, contain a highly conserved two-heme motif supporting cross-membrane electron transport (ET) that connects the two catalytic quinone-binding sites (Q_n and Q_p). Typically, this ET occurs from the low- to high-potential heme b, but in photosynthetic cytochrome b₆f, the redox midpoint potentials (E_ms) of these hemes remain uncertain. Our systematic redox titration analysis based on three independent and comprehensive low-temperature spectroscopies (continuous wave and pulse electron paramagnetic resonance (EPR) and optical spectroscopies) allowed for unambiguous assignment of spectral components of hemes in cytochrome b₆f and rev

SUBMITTER: Szwalec M 

PROVIDER: S-EPMC9720722 | biostudies-literature | 2022 Dec

REPOSITORIES: biostudies-literature