Evidence of protein-tyrosine kinase activity in the bacterium Acinetobacter calcoaceticus.
Protein phosphorylation was investigated in the bacterium Acinetobacter calcoaceticus both in vivo and in vitro. In cells grown with [32P]orthophosphate, several radioactive phosphoproteins were detected by gel electrophoresis and autoradiography. These proteins were shown to contain phosphoserine, phosphothreonine, and a relatively large proportion of phosphotyrosine residues. Incubation of cellular extracts with [gamma-32P] ATP also resulted in the phosphorylation of several proteins. At least four of them, namely an 81-kDa protein, were modified at tyrosine. No protein labeling occurred when extracts were incubated with [gamma-32P] ATP or [14C]ATP. Moreover, phosphoproteins were insensitive to snake venom phosphodiesterase. All together these results indicate that A. calcoaceticus harbors different protein kinases including a protein-tyrosine kinase activity. Further analysis of this activity showed that it has little, if any, functional similarity with eukaryotic protein-tyrosine kinases.
Dadssi
M
M
Institute of Biology and Chemistry of Proteins, Centre National de la Recherche Scientifique, University of Lyon, Villeurbanne, France.
Cozzone
A J
AJ
D000150:Acinetobacter / Q000201:enzymology*; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D001426:Bacterial Proteins / Q000302:isolation & purification / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010750:Phosphoproteins / Q000302:isolation & purification*; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D013379:Substrate Specificity
D000596:Amino Acids; D001426:Bacterial Proteins; D010750:Phosphoproteins; D011505:Protein-Tyrosine Kinases