2.4.1.264	malfunction	a transposon responsible for the mutation is located within gumK gene. The Tn5 insertion mutant with a reduced slimy phenotype fails to produce the pentasaccharide repeating-unit of xanthan. Only three sugars are transferred to the prenyl phosphate intermediate. The lipid-associated saccharide is the trisaccharide reducing end of the pentasaccharide from the wild-type strain. This trisaccharide is built up from UDP-Glc and GDP-Man, and a glucose residue is at the reducing end, linked to an allylic prenol through a diphosphate bridge. the trisaccharide-PP-polyprenol is the precursor of the polymer. This new polymer, a polytrisaccharide, is detected also in vivo. A recombinant plasmid with the whole gum cluster restored the wild type phenotype	703048	
2.4.1.264	malfunction	from the biochemical analysis of a defined set of Xanthomonas campestris gum mutants, experimental data are reported for assigning functions to the products of the gum genes. Inactivation of gumK completely abolishes in vitro polymer formation. Permeabilized cells are incubated with UDP-glucose, GDP-mannose, and UDP-glucuronic acid, one of them labeled in the sugar moiety. Accumulating intermediates are analysed. The gumK deletion strain produces a very low amount of polymer in vivo (polytrimer). Mutations in gumK gene has less effect on the amount of in vitro produced polysaccharide	704257	
2.4.1.264	malfunction	significantly attenuated production of xanthan in knock-out mutant strain	702828	
2.4.1.264	physiological function	GumK is involved in biosynthesis of the pentasaccharide repeating unit of xanthan	702828	
2.4.1.264	physiological function	the enzyme is involved in biosynthesis of the exopolysaccharide xanthan	701482	
2.4.1.264	physiological function	the enzyme is involved in biosynthesis of xanthan	704257, 704434