Domain

GlmU, C-terminal LbH domain (IPR038009)

Short name: GlmU_C_LbH

Overlapping homologous superfamilies

Domain relationships

None.

Description

N-Acetylglucosamine-1-PO(4) uridyltransferase (GlmU, EC:2.7.7.23) is a trimeric bifunctional enzyme that catalyzes the last two sequential reactions in the de novo biosynthetic pathway for UDP-GlcNAc.

The X-ray crystal structure of Escherichia coli GlmU in complex with UDP-GlcNAc and CoA has been determined to 2.1 A resolution and reveals a two-domain architecture that is responsible for these two reactions [PMID: 11329257]. The C-terminal domain is responsible for the CoA-dependent acetylation of Glc-1-PO(4) to GlcNAc-1-PO(4) and displays the longest left-handed parallel beta-helix (LbetaH or LbH) observed to date. The acetyltransferase active site defined by the binding site for CoA makes use of residues from all three subunits and is positioned beneath an open cavity large enough to accommodate the Glc-1-PO(4) acetyl acceptor. The N-terminal domain catalyzes uridyl transfer from UTP to GlcNAc-1-PO(4) to form the final products UDP-GlcNAc and pyrophosphate. This domain is composed of a central seven-stranded beta-sheet surrounded by six alpha-helices in a Rossmann fold-like topology.

This entry represents the C-terminal LbH domain that possesses the acetyltransferase activity. It catalyzes the CoA-dependent acetylation of GlcN-1-phosphate to GlcNAc-1-phosphate. The LbH domain contains 10 turns, each containing three imperfect tandem repeats of a hexapeptide repeat motif (X-[STAV]-X-[LIV]-[GAED]-X. The acetyltransferase active site is located at the interface between two subunits of the active LbH trimer [PMID: 17473010, PMID: 11118459].

GO terms

Biological Process

GO:0006048 UDP-N-acetylglucosamine biosynthetic process

Molecular Function

GO:0003977 UDP-N-acetylglucosamine diphosphorylase activity
GO:0019134 glucosamine-1-phosphate N-acetyltransferase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
CDD