Conformational changes on substrate binding revealed by structures of Methylobacterium extorquens malate dehydrogenase.
Acta Crystallogr F Struct Biol Commun
; 74(Pt 10): 610-616, 2018 Oct 01.
Article
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| MEDLINE
| ID: mdl-30279311
ABSTRACT
Three high-resolution X-ray crystal structures of malate dehydrogenase (MDH; EC 1.1.1.37) from the methylotroph Methylobacterium extorquens AM1 are presented. By comparing the structures of apo MDH, a binary complex of MDH and NAD+, and a ternary complex of MDH and oxaloacetate with ADP-ribose occupying the pyridine nucleotide-binding site, conformational changes associated with the formation of the catalytic complex were characterized. While the substrate-binding site is accessible in the enzyme resting state or NAD+-bound forms, the substrate-bound form exhibits a closed conformation. This conformational change involves the transition of an α-helix to a 310-helix, which causes the adjacent loop to close the active site following coenzyme and substrate binding. In the ternary complex, His284 forms a hydrogen bond to the C2 carbonyl of oxaloacetate, placing it in a position to donate a proton in the formation of (2S)-malate.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Proteínas Bacterianas
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Adenosina Difosfato Ribosa
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Ácido Oxaloacético
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Methylobacterium extorquens
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Malato Deshidrogenasa
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Malatos
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NAD
Idioma:
En
Revista:
Acta Crystallogr F Struct Biol Commun
Año:
2018
Tipo del documento:
Article
País de afiliación:
Argentina