A gene pknA, coding for an eukaryotic-type protein Ser/Thr kinase, was cloned from the Streptomyces coelicolor A3(2) chromosome. The PknA protein kinase, containing the C-terminal eukaryotic-type kinase domain with an N-terminal extension, was expressed in Escherichia coli and Streptomyces lividans. The affinity purified MBP-PknA fusion protein was assayed for kinase activity that showed its ability to autophosphorylate in vitro in the presence of [gamma-32P]ATP. The activity was Mn2+ dependent. The preautophosphorylated kinase phosphorylated at least two proteins (sizes 30 and 32 kDa) in the S. coelicolor J1501 cell-free extracts of all developmental stages. The larger of them was also phosphorylated in vitro by an endogenous protein kinase in late stages extracts, but not earlier. Although Mn2+ dependent protein phosphorylation has previously been described in Streptomyces, this is the first report of a gene encoding such an enzyme in this genus.

Institute of Microbiology ASCR Vídenská 1083 Prague 142 20 Czech Republic

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Comparative study of the life cycle dependent post-translation modifications of protein synthesis elongation factor Tu present in the membrane proteome of streptomycetes and mycobacteria

Protein synthesis elongation factor Tu present in spores of Streptomyces coelicolor can be phosphorylated in vitro by the spore protein kinase