Open AccessStructure of Escherichia coli aspartate α‐decarboxylase Asn72Ala: probing the role of Asn72 in pyruvoyl cofactor formation
Author(s) -
Webb Michael E.,
Lobley Carina M. C.,
Soliman Fatima,
Kilkenny Mairi L.,
Smith Alison G.,
Blundell Tom L.,
Abell Chris
Publication year - 2012
Publication title -
acta crystallographica section f
Language(s) - English
Resource type - Journals
ISSN - 1744-3091
DOI - 10.1107/s1744309112009487
Subject(s) - active site , cofactor , escherichia coli , serine , mutant , chemistry , hydrolysis , stereochemistry , biochemistry , catalysis , enzyme , gene
The crystal structure of the Asn72Ala site‐directed mutant of Escherichia coli aspartate α‐decarboxylase (ADC) has been determined at 1.7 Å resolution. The refined structure is consistent with the presence of a hydrolysis product serine in the active site in place of the pyruvoyl group required for catalysis, which suggests that the role of Asn72 is to protect the ester formed during ADC activation from hydrolysis. In previously determined structures of activated ADC, including the wild type and other site‐directed mutants, the C‐terminal region of the protein is disordered, but in the Asn72Ala mutant these residues are ordered owing to an interaction with the active site of the neighbouring symmetry‐related multimer.