A plant receptor-like gene, the S-locus receptor kinase of Brassica oleracea L., encodes a functional serine/threonine kinase.
To investigate the catalytic properties of the Brassica oleracea S-locus receptor kinase (SRK), we have expressed the domain that is homologous to protein kinases as a fusion protein in Escherichia coli. Following in vivo labeling of cultures with 32P-labeled inorganic phosphate, we observed phosphorylation of the fusion protein on serine and threonine, but not on tyrosine. In contrast, labeling was not observed when lysine-524, a residue conserved among all protein kinases, was mutated to arginine, thus confirming that SRK phosphorylation was the result of intrinsic serine/threonine kinase activity.
Stein
J C
JC
Division of Biological Sciences, Cornell University, Ithaca, New York 14853.
Nasrallah
J B
JB
D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D001937:Brassica / Q000201:enzymology / Q000235:genetics*; D004247:DNA; D017343:Genes, Plant; D008969:Molecular Sequence Data; D010766:Phosphorylation; D010940:Plant Proteins; D011494:Protein Kinases / Q000235:genetics*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism
D010940:Plant Proteins; D004247:DNA; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; C079832:S-receptor kinase