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Glucosamine-6-phosphate synthase from Escherichia coli: Determination of the mechanism of inactivation by N sup 3 -fumaroyl-L-2,3-diaminopropionic derivatives

Journal Article · · Biochemistry; (USA)
DOI:https://doi.org/10.1021/bi00467a012· OSTI ID:6324622
; ; ;  [1]
  1. Laboratoire de Bioorganique et Biotechnologies, Paris (France)

A mechanistic investigation of the inactivation of Escherichia coli glucosamine-6-phosphate synthase by N{sup 3}-(4-methoxyfumaroyl)-L-2,3-diaminopropionate (FMDP) was undertaken. On the basis of the known participation of the N-terminal cysteine residue in this process, the model reactions between FMDP and L-cysteine and between FMDP and the synthetic decapeptide Cys-Gly-Ile-Val-Gly-Ala-Ile-Ala-Ile-Ala-Gln-Arg, corresponding to the amino-terminal protein sequence, were studied. The results allowed us to propose a pathway that is in perfect agreement with the biochemical results: enzyme inactivation arose from Michael addition of glutamine binding site cysteine-1 on the fumaroyl double bond at the {beta}-position of the ester group. Upon denaturation under slightly alkaline conditions, this adduct underwent cyclization to a transient succinimide adduct, which rearranged into the stable 2-substituted 1,4-thiazin-3-one-5-carboxylate involving participation of the cysteine amino group. The tryptic radiolabeled peptides purified from ({sup 3}H)FMDP-treated enzyme and resistant to Edman degradation coeluted with the products resulting from the model reaction between the synthetic decapeptide and the inhibitor.

OSTI ID:
6324622
Journal Information:
Biochemistry; (USA), Journal Name: Biochemistry; (USA) Vol. 29:15; ISSN 0006-2960; ISSN BICHA
Country of Publication:
United States
Language:
English