Pkg2, a Novel Transmembrane Protein Ser/Thr Kinase of Streptomyces granaticolor |
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Authors: | Richard N dvorní k, Tom Vomastek, Ji í Jane
ek, Zuzana Technikov , Pavel Branny |
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Affiliation: | Richard Nádvorník, Tomáš Vomastek, Jiří Janeček, Zuzana Techniková, and Pavel Branny |
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Abstract: | A 4.2-kb SphI-BamHI fragment of chromosomal DNA from Streptomyces granaticolor was cloned and shown to encode a protein with significant sequence similarity to the eukaryotic protein serine/threonine kinases. It consists of 701 amino acids and in the N-terminal part contains all conserved catalytic domains of protein kinases. The C-terminal domain of Pkg2 contains seven tandem repeats of 11 or 12 amino acids with similarity to the tryptophan-docking motif known to stabilize a symmetrical three-dimensional structure called a propeller structure. The pkg2 gene was overexpressed in Escherichia coli, and the gene product (Pkg2) has been found to be autophosphorylated at serine and threonine residues. The N- and C-terminal parts of Pkg2 are separated with a hydrophobic stretch of 21 amino acids which translocated a PhoA fusion protein into the periplasm. Thus, Pkg2 is the first transmembrane protein serine/threonine kinase described for streptomycetes. Replacement of the pkg2 gene by the spectinomycin resistance gene resulted in changes in the morphology of aerial hyphae. |
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