A serine/threonine protein kinase from Mycobacterium tuberculosis.
Genomic DNA sequencing in the vicinity of the pstA-1 gene from Mycobacterium tuberculosis allowed us to clone, sequence and identify a gene encoding a 70-kDa protein. The size of the protein was confirmed by in vitro coupled transcription/translation. Its N-terminal domain shows extensive sequence similarity with the catalytic domain of eukaryotic serine/threonine protein kinases, and the protein was therefore called Mbk (mycobacterial protein kinase). The deduced amino acid sequence contains two transmembrane segments, which flank a highly repetitive region, suggesting a receptor-like anchoring. The mbk gene was overexpressed in Escherichia coli and the gene product (Mbk) was purified as a fusion protein with gluthatione S-transferase. Recombinant Mbk was found to be autophosphorylated on threonine residues and capable of phosphorylating myelin basic proteins from bovine brain and histones from calf thymus on serine residues, both in a manganese-dependent manner. The phosphorylation of myelin basic proteins by Mbk was inhibited by calcium and by staurosporine, a widely used inhibitor of eukaryotic protein serine/threonine kinases. A similar gene was found in Mycobacterium bovis BCG DNA by Southern blot analysis. Its expression was detected in cultures of M. bovis BCG by reverse transcriptase/PCR. Although its biological role is unknown, it is the first serine/threonine protein kinase characterized in Mycobacteria.
Peirs
P
P
Departement of Virology, Institut Pasteur, Brussels, Belgium.
De Wit
L
L
Braibant
M
M
Huygen
K
K
Content
J
J
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D009163:Mycobacterium bovis / Q000201:enzymology / Q000235:genetics; D009169:Mycobacterium tuberculosis / Q000201:enzymology* / Q000235:genetics*; D010802:Phylogeny; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D013045:Species Specificity
D004269:DNA, Bacterial; D011993:Recombinant Fusion Proteins; D017346:Protein Serine-Threonine Kinases