Open AccessThreonine 57 is required for the post‐translational activation of Escherichia coli aspartate α‐decarboxylase
Author(s) -
Webb Michael E.,
Yorke Briony A.,
Kershaw Tom,
Lovelock Sarah,
Lobley Carina M. C.,
Kilkenny Mairi L.,
Smith Alison G.,
Blundell Tom L.,
Pearson Arwen R.,
Abell Chris
Publication year - 2014
Publication title -
acta crystallographica section d
Language(s) - English
Resource type - Journals
ISSN - 1399-0047
DOI - 10.1107/s1399004713034275
Subject(s) - threonine , serine , site directed mutagenesis , mutant , residue (chemistry) , chemistry , biosynthesis , active site , biochemistry , stereochemistry , alanine , transferase , escherichia coli , enzyme , amino acid , gene
Aspartate α‐decarboxylase is a pyruvoyl‐dependent decarboxylase required for the production of β‐alanine in the bacterial pantothenate (vitamin B 5 ) biosynthesis pathway. The pyruvoyl group is formed via the intramolecular rearrangement of a serine residue to generate a backbone ester intermediate which is cleaved to generate an N‐terminal pyruvoyl group. Site‐directed mutagenesis of residues adjacent to the active site, including Tyr22, Thr57 and Tyr58, reveals that only mutation of Thr57 leads to changes in the degree of post‐translational activation. The crystal structure of the site‐directed mutant T57V is consistent with a non‐rearranged backbone, supporting the hypothesis that Thr57 is required for the formation of the ester intermediate in activation.