Reaction mechanism of the bioluminescent protein mnemiopsin1 revealed by X-ray crystallography and QM/MM simulations.

ABSTRACT: Bioluminescence of a variety of marine organisms, mostly cnidarians and ctenophores, is carried out by Ca²⁺-dependent photoproteins. The mechanism of light emission operates via the same reaction in both animal families. Despite numerous studies on the ctenophore photoprotein family, the detailed catalytic mechanism and arrangement of amino acid residues surrounding the chromophore in this family are a mystery. Here, we report the crystal structure of Cd²⁺-loaded apo-mnemiopsin1, a member of the ctenophore family, at 2.15 Å resolution and used quantum mechanics/molecular mechanics (QM/MM) to investigate its reaction mechanism. The simulations suggested that an Asp-156-Arg-39-Tyr-202 triad creates a hydrogen-bonded network to facilitate the transfer of a proton from th

SUBMITTER: Molakarimi M 

PROVIDER: S-EPMC6322872 | biostudies-literature | 2019 Jan

REPOSITORIES: biostudies-literature