Substrate Enolate Intermediate and Mimic Captured in the Active Site of Streptomyces coelicolor Methylmalonyl-CoA Epimerase.
Chembiochem
; 23(2): e202100487, 2022 01 19.
Article
en En
| MEDLINE
| ID: mdl-34856049
ABSTRACT
Methylmalonyl-CoA epimerase (MMCE) is proposed to use general acid-base catalysis, but the proposed catalytic glutamic acids are highly asymmetrical in the active site unlike many other racemases. To gain insight into the puzzling relationships between catalytic mechanism, structure, and substrate preference, we solved Streptomyces coelicolor MMCE structures with substrate or 2-nitropropionyl-CoA, an intermediate/transition state analogue. Both ligand bound structures have a planar methylmalonate/2-nitropropionyl moiety indicating a deprotonated C2 with ≥4â
Å distances to either catalytic acid. Both glutamates interact with the carboxylate/nitro group, either directly or through other residues. This suggests the proposed catalytic acids sequentially catalyze proton shifts between C2 and carboxylate of the substrate with an enolate intermediate. In addition, our structures provide a platform to design mutations for expanding substrate scope to support combinatorial biosynthesis.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Racemasas y Epimerasas
/
Streptomyces coelicolor
Límite:
Humans
Idioma:
En
Revista:
Chembiochem
Asunto de la revista:
BIOQUIMICA
Año:
2022
Tipo del documento:
Article
País de afiliación:
Estados Unidos