Nucleotidylation, not phosphorylation, is the major source of the phosphotyrosine detected in enteric bacteria.
The majority of the phosphotyrosine recovered from partial acid hydrolysates of 32P-labeled Escherichia coli is derived from a single prominent protein. We show here by biochemical, genetic, and immunological criteria that this protein is actually glutamine synthetase adenylylated (not phosphorylated) at tyrosine. Furthermore, all of the phosphotyrosine detectable in partial acid hydrolysates of 32P-labeled Salmonella typhimurium was eliminated in a strain deficient in both glutamine synthetase and uridylyltransferase, an enzyme which uridylylates the regulatory protein PII at a tyrosine residue. These results suggest that protein-tyrosine phosphorylation represents a rare modification in eubacterial cells.
Foster
R
R
Department of Biochemistry, University of California, Berkeley 94720.
Thorner
J
J
Martin
G S
GS
D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D005974:Glutamate-Ammonia Ligase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D006868:Hydrolysis; D008970:Molecular Weight; D010710:Phosphates / Q000378:metabolism; D010761:Phosphorus Radioisotopes; D010766:Phosphorylation; D010768:Phosphoserine / Q000302:isolation & purification; D010769:Phosphothreonine / Q000302:isolation & purification; D019000:Phosphotyrosine; D011865:Radioisotope Dilution Technique; D012486:Salmonella typhimurium / Q000235:genetics / Q000378:metabolism*; D013045:Species Specificity; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000302:isolation & purification
D010710:Phosphates; D010761:Phosphorus Radioisotopes; D010769:Phosphothreonine; D010768:Phosphoserine; D019000:Phosphotyrosine; D014443:Tyrosine; D005974:Glutamate-Ammonia Ligase