Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2002 Dec 24;41(51):15410-4.
doi: 10.1021/bi026384i.

New UDP-GlcNAc C4 Epimerase Involved in the Biosynthesis of 2-acetamino-2-deoxy-L-altruronic Acid in the O-antigen Repeating Units of Plesiomonas Shigelloides O17

Affiliations

New UDP-GlcNAc C4 Epimerase Involved in the Biosynthesis of 2-acetamino-2-deoxy-L-altruronic Acid in the O-antigen Repeating Units of Plesiomonas Shigelloides O17

Przemyslaw Kowal et al. Biochemistry. .

Abstract

Plesiomonas shigelloides is a ubiquitous waterborne pathogen responsible for diseases such as diarrhea and bacillary dysentery, commonly afflicting infants and children. This bacterium is endowed with an O-antigen gene cluster consisting of 10 consecutive reading frames. One of these, designated wbgU (orf3), has been overexpressed and biochemically characterized to show that it encodes a uridine diphosphate-N-acetylglucosamine (UDP-GlcNAc) C4 epimerase, only the second microbial enzyme characterized to have this activity. Epimerization is an equilibrium reaction resulting in a 70:30 ratio of UDP-GlcNAc to uridine diphosphate-N-acetylgalactosamine (UDP-GalNAc), irrespective of the initial substrate. The K(m) values for UDP-GalNAc and UDP-GlcNAc are 131 microM and 137 microM, respectively. WbgU is also capable of converting nonacetylated derivatives but with much lower efficiency. It contains a tightly bound nicotinamide adenine dinucleotide [NAD(H)] molecule and requires no other cofactors for activity. We propose here that this enzyme catalyzes the first of the three transformations in the biosynthetic pathway of 2-acetamino-2-deoxy-L-altruronic acid, an unusual sugar present in the O-specific side chains of lipopolysaccharide of P. shigelloides O17 and its close relative Escherichia coli Sonnei.

Similar articles

See all similar articles

Cited by 9 articles

See all "Cited by" articles

Publication types

MeSH terms

LinkOut - more resources

Feedback