Identification of hydrogen bonding network for proton transfer at the quinol oxidation site of Rhodobacter capsulatus cytochrome bc₁.

ABSTRACT: Cytochrome bc₁ catalyzes electron transfer from quinol (QH₂) to cytochrome c in reactions coupled to proton translocation across the energy-conserving membrane. Energetic efficiency of the catalytic cycle is secured by a two-electron and two-proton bifurcation reaction leading to oxidation of QH₂ and reduction of the Rieske cluster and heme b_L. The proton paths associated with this reaction remain elusive. Here, we used site-directed mutagenesis and quantum mechanical calculations to analyze the contribution of protonable side chains located at the heme b_L side of the QH₂ oxidation site in Rhodobacter capsulatus cytochrome bc₁. We observe that the proton path is effectively switched off when H276 and E295 are simu

SUBMITTER: Borek A 

PROVIDER: S-EPMC10583091 | biostudies-literature | 2023 Oct

REPOSITORIES: biostudies-literature