Double crossed? Structural and computational studies of an unusually crosslinked haem in <i>Methylococcus capsulatus</i> cytochrome P460.

ABSTRACT: Cytochromes P460 oxidise hydroxylamine within the nitrogen cycle and contain as their active site an unusual catalytic c-type haem where the porphyrin is crosslinked to the protein via a lysine residue in addition to the canonical cross links from cysteine residues. Understanding how enzymes containing P460 haem oxidise hydroxylamine into either nitrous oxide or nitric oxide has implications for climate change. Interestingly the P460-containing hydroxylamine oxidoreductase utilises a tyrosine crosslink to haem and performs similar chemistry. Previous crystal structures of cytochrome P460 from Nitrosomonas europaea (NeP460) clearly show the existence of a single crosslink between the NZ atom of lysine and the haem porphyrin, with mutagenesis studies indicating roles for

SUBMITTER: Pfalzgraf HE 

PROVIDER: S-EPMC12352625 | biostudies-literature | 2025 Sep

REPOSITORIES: biostudies-literature