Xanthosine utilization in Salmonella enterica serovar Typhimurium is recovered by a single aspartate-to-glycine substitution in xanthosine phosphorylase.
xapABR from Salmonella enterica was analyzed and compared with the corresponding Escherichia coli genes. xapB and xapR, but not xapA, encode functional proteins. An S. enterica XapA(Asp72Gly) mutant that restores the phosphorolytic activity was selected. The purified mutant enzyme has different kinetic constants than the E. coli enzyme but similar substrate specificity.
Hansen
Michael Riis
MR
Department of Biological Chemistry, Institute of Molecular Biology and Physiology, University of Copenhagen, Sølvgade 83 H, 1307 Copenhagen K, Denmark.
Tranekjaer Jørgensen
Jesper
J
Dandanell
Gert
G
D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001224:Aspartic Acid; D005998:Glycine; D008969:Molecular Sequence Data; D011683:Purine-Nucleoside Phosphorylase / Q000235:genetics* / Q000378:metabolism*; D015183:Restriction Mapping; D012263:Ribonucleosides / Q000378:metabolism*; D012486:Salmonella typhimurium / Q000201:enzymology* / Q000235:genetics; D014970:Xanthines
D012263:Ribonucleosides; D014970:Xanthines; D001224:Aspartic Acid; C005893:xanthosine; C028449:xanthosine phosphorylase; D011683:Purine-Nucleoside Phosphorylase; D005998:Glycine