Serine/threonine protein kinases PknF and PknG of Mycobacterium tuberculosis: characterization and localization.
Pathogenesis of Mycobacterium tuberculosis is closely connected to its survival and replication within the host. Some pathogenic bacteria employ protein kinases that interfere with the cellular signalling network of host cells and promote bacterial survival. In this study, the pknF and pknG genes, which encode two putative protein kinases of M. tuberculosis H(37)Rv, protein kinase F (PknF) and protein kinase G (PknG), respectively, were cloned and expressed in Escherichia coli. Purified PknF phosphorylated the peptide substrate myelin basic protein (MBP) at serine and threonine residues, while purified PknG phosphorylated only at serine residues. The activity of the two kinases was abrogated by mutation of the codon for the predicted ATP-binding-site lysine residue. Southern blot analysis revealed that homologues of the genes encoding the two kinases are present in M. tuberculosis H(37)Ra and Mycobacterium bovis BCG, but not in Mycobacterium smegmatis. Immunoblot analysis of various cellular fractions of M. tuberculosis H(37)Rv revealed that PknF is a transmembrane protein and that PknG is predominantly a cytosolic enzyme. The present study should aid in elucidating the role of these protein kinases in the pathogenesis of mycobacteria.
Koul
Anil
A
Department of Molecular Biology, Max-Planck-Institut für Biochemie, Am Klopferspitz 18A, 82152 Martinsried, Germany5.|Department of Biochemistry, University of Delhi South Campus, N. Delhi, India3.|Centre for Biochemical Technology, Mall Road, Delhi-110 007, India1.
Choidas
Axel
A
Axxima Pharmaceuticals AG, Am Klopferspitz 19, 82152 Martinsried, Germany2.
Tyagi
Anil K
AK
Department of Biochemistry, University of Delhi South Campus, N. Delhi, India3.
Drlica
Karl
K
Public Health Research Institute, 455 First Avenue, NY, USA4.
Singh
Yogendra
Y
Centre for Biochemical Technology, Mall Road, Delhi-110 007, India1.
Ullrich
Axel
A
Department of Molecular Biology, Max-Planck-Institut für Biochemie, Am Klopferspitz 18A, 82152 Martinsried, Germany5.
D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology; D003001:Cloning, Molecular; D003600:Cytosol / Q000201:enzymology; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000201:enzymology* / Q000235:genetics; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
D001426:Bacterial Proteins; D017346:Protein Serine-Threonine Kinases; C000605609:protein kinase G, Mycobacterium tuberculosis