1krr
From Proteopedia
Galactoside Acetyltransferase in Complex with Acetyl-Coenzyme A
Overview
The galactoside acetyltransferase (thiogalactoside transacetylase) of Escherichia coli (GAT, LacA, EC 2.3.1.18) is a gene product of the classical lac operon. GAT may assist cellular detoxification by acetylating nonmetabolizable pyranosides, thereby preventing their reentry into the cell. The structure of GAT has been solved in binary complexes with acetyl-CoA or CoA and in ternary complexes with CoA and the nonphysiological acceptor substrates isopropyl beta-D-thiogalactoside (IPTG) or p-nitrophenyl beta-D-galactopyranoside (PNPbetaGal). A hydrophobic cleft that binds the thioisopropyl and p-nitrophenyl aglycones of IPTG and PNPbetaGal may discriminate against substrates with hydrophilic substituents at this position, such as lactose, or inducers of the lac operon. An extended loop projecting from the left-handed parallel beta helix domain contributes His115, which is in position to facilitate attack of the C6-hydroxyl group of the substrate on the thioester.
About this Structure
1KRR is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Structure of the lac operon galactoside acetyltransferase., Wang XG, Olsen LR, Roderick SL, Structure. 2002 Apr;10(4):581-8. PMID:11937062 Page seeded by OCA on Fri May 2 23:05:30 2008
