Stalling chromophore synthesis of the fluorescent protein Venus reveals the molecular basis of the final oxidation step.

ABSTRACT: Fluorescent proteins (FPs) have revolutionised the life sciences, but the mechanism of chromophore maturation is still not fully understood. Here we show that incorporation of a photo-responsive non-canonical amino acid within the chromophore stalls maturation of Venus, a yellow FP, at an intermediate stage; a crystal structure indicates the presence of O₂ located above a dehydrated enolate form of the imidazolone ring, close to the strictly conserved Gly67 that occupies a twisted conformation. His148 adopts an "open" conformation so forming a channel that allows O₂ access to the immature chromophore. Absorbance spectroscopy supported by QM/MM simulations suggests that the first oxidation step involves formation of a hydroperoxyl intermediate in conjunction with dehyd

SUBMITTER: Auhim HS 

PROVIDER: S-EPMC8188506 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature