@article {1464,
	title = {PseG of pseudaminic acid biosynthesis - A UDP-sugar hydrolase as a masked glycosyltransferase},
	journal = {Journal of Biological Chemistry},
	volume = {281},
	number = {30},
	year = {2006},
	note = {ISI Document Delivery No.: 065VFTimes Cited: 12Cited Reference Count: 40Liu, Feng Tanner, Martin E.},
	month = {Jul},
	pages = {20902-20909},
	type = {Article},
	abstract = {The flagellin proteins in pathogenic bacteria such as Campylobacter jejuni and Helicobacter pylori are heavily glycosylated with the nine-carbon alpha-keto acid, pseudaminic acid. The presence of this posttranslational modification is absolutely required for assembly of functional flagella. Since motility is required for colonization, pseudaminic acid biosynthesis represents a virulence factor in these bacteria. Pseudaminic acid is generated from UDP-N-acetylglucosamine in five biosynthetic steps. The final step has been shown to involve the condensation of 2,4-diacetamido- 2,4,6-trideoxy-L-altrose ( 6-deoxy-AltdiNAc) with phosphoenolpyruvate as catalyzed by the enzyme pseudaminic acid synthase, NeuB3. The 6-deoxy-AltdiNAc used in this process is generated from its nucleotide-linked form, UDP-6-deoxy-AltdiNAc, by the action of a hydrolase that cleaves the glycosidic bond and releases UDP. This manuscript describes the first characterization of a UDP-6-deoxy-AltdiNAc hydrolase, namely PseG ( Cj1312) from C. jejuni. The activity of this enzyme is independent of the presence of divalent metal ions, and the values of the catalytic constants were found to be k(cat) = 27 s(-1) and K-m = 174 mu M. The enzyme was shown to hydrolyze the substrate with an overall inversion of stereochemistry at C-1 and to utilize a C-O bond cleavage mechanism during catalysis. These results, coupled with homology comparisons, suggest that the closest ancestors to the hydrolase are members of the metal-independent GT-B family of glycosyltransferases that include the enzyme MurG.},
	keywords = {CAMPYLOBACTER-JEJUNI, FLAGELLIN, FUNCTIONAL-CHARACTERIZATION, GLYCOPROTEINS, glycosylation, HELICOBACTER-PYLORI, IDENTIFICATION, MECHANISM, N-ACETYLGLUCOSAMINE 2-EPIMERASE, NUDIX HYDROLASES, SYNTHASE},
	isbn = {0021-9258},
	url = {<Go to ISI>://000239187300027},
	author = {Liu, F. and Tanner, M. E.}
}
