title: Depression of guanosine diphosphate-mannose pyrophosphorylase by mutations in two different regulator genes involved in capsular polysaccharide synthesis in Escherichia coli K-12.
abstract: Mutations in a regulator gene (capR) that causes increased synthesis of capsular polysaccharide and derepressed synthesis of several enzymes involved in polysaccharide synthesis also derepress synthesis of guanosine diphosphate (GDP)-mannose pyrophosphorylase. In addition, a second mucoid mutation (capS, which maps separately from capR) also results in the derepression of GDP-mannose pyrophosphorylase. New conditions for assaying GDP-mannose hydrolyase and GDP-l-fucose synthetase permitted us to show that these enzymes are also derepressed in the capS mucoid strain. Although phosphomannose isomerase and uridine diphosphate-galactose-4-epimerase are derepressed in capR mucoid strains, they are not derepressed in capS mucoid strains. A nonmucoid mutant of a strain containing the capR9 (mucoid) allele was deficient in GDP-mannose pyrophosphorylase.
mesh_terms: D002473:Cell Wall / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology* / Q000378:metabolism; D005809:Genes, Regulator; D005827:Genetics, Microbial; D006026:Glycoside Hydrolases / Q000378:metabolism; D006150:Guanine Nucleotides; D007535:Isomerases / Q000378:metabolism; D008025:Ligases / Q000378:metabolism; D009154:Mutation; D009713:Nucleotidyltransferases / Q000378:metabolism; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis*; D014500:Uracil Nucleotides
chemical_list: D006150:Guanine Nucleotides; D011135:Polysaccharides, Bacterial; D014500:Uracil Nucleotides; D009713:Nucleotidyltransferases; D006026:Glycoside Hydrolases; D007535:Isomerases; D008025:Ligases