The lac operon galactoside acetyltransferase.
Of the proteins encoded by the three structural genes of the lac operon, the galactoside acetyltransferase (thiogalactoside transacetylase, LacA, GAT) encoded by lacA is the only protein whose biological role remains in doubt. Here, we briefly note the classical literature that led to the identification and initial characterization of GAT, and focus on more recent results which have revealed its chemical mechanism of action and its membership in a large superfamily of structurally similar acyltransferases. The structural and sequence similarities of several members of this superfamily confirm the original claim for GAT as a CoA-dependent acetyltransferase specific for the 6-hydroxyl group of certain pyranosides, but do not yet point to the identity of the natural substrate(s) of the enzyme.
Roderick
Steven L
SL
Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA. roderick@aecom.yu.edu
D000123:Acetyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D001665:Binding Sites; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D007700:Kinetics; D007763:Lac Operon; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D013379:Substrate Specificity
D000123:Acetyltransferases; C022770:galactoside acetyltransferase