Methionine coordination to the heme iron and its displacement by nitric oxide in the CcoP subunit of Pseudomonas aeruginosa cytochrome cbb₃ oxidase.

ABSTRACT: Ligand substitution is common in signaling mechanisms of heme proteins. Methionine at the heme iron can get displaced by both endogenous and exogeneous ligands, including NO. The latter is particularly relevant in low-O₂ environments and affects properties of metalloproteins in electron-transfer (ET) chains. Inspection of the recent cryo-EM structures of cytochrome (cyt) cbb₃ oxidases from Pseudomonas aeruginosa (Pa) suggested that FeS(Met) distances in the CcoP subunit are too long for Met ligation to the heme iron, yet this ligation is critical for high reduction potentials to support downhill ET to this terminal oxidase. Using spectroscopic and electrochemical characterization, we show that the two hemes of the CcoP subunit of Pa cbb₃-2 oxidase (CcoP2) a

SUBMITTER: Yang J 

PROVIDER: S-EPMC12834235 | biostudies-literature | 2026 Feb

REPOSITORIES: biostudies-literature