Cytochrome aa₃ Oxygen Reductase Utilizes the Tunnel Observed in the Crystal Structures To Deliver O₂ for Catalysis.

ABSTRACT: Cytochrome aa₃ is the terminal respiratory enzyme of all eukaryotes and many bacteria and archaea, reducing O₂ to water and harnessing the free energy from the reaction to generate the transmembrane electrochemical potential. The diffusion of O₂ to the heme-copper catalytic site, which is buried deep inside the enzyme, is the initiation step of the reaction chemistry. Our previous molecular dynamics (MD) study with cytochrome ba₃, a homologous enzyme of cytochrome aa₃ in Thermus thermophilus, demonstrated that O₂ diffuses from the lipid bilayer to its reduction site through a 25 Å long tunnel inferred by Xe binding sites detected by X-ray crystallography [Mahinthichaichan, P., Gennis, R., and Tajkhorshid, E. (2016) Biochemis

SUBMITTER: Mahinthichaichan P 

PROVIDER: S-EPMC5936630 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature