| A lot of Serine/Threonine protein kinases were found in Streptomyces species.They might play some important roles in the growth, morphological development and differentiation and secondary metabolism processes, when the presence of ATP and other phosphate donor, the hydroxyl groups on serine/threonine residues of substrate proteins, which were phosphorylated specifically, and leading to changes in the protein activities and characteristics. Its function studies will help us penetratingly, to understand the regular patterns of life activities of Streptomyces.Streptomyces vietnamensis GIMV4.0001, a newly designated streptomycete species was from the soil of tropical forests, that was isolated by Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, was found to be a new granaticin producer. A putative serine/threonine kinase gene, gra-orf7, was found in the left end of the granaticin gene cluster. To deduce its possible physiological role in S. vietnamensis, a gra-orf7gene deletion mutant was constructed successfully, using a PCR-targeting disruption method.The phenotypic analysis of the mutant showed no visible changes in colony and spore morphology, sporulation, or granaticin production. However, the mutant tended to synthesize granaticin at earlier stage by1hour than the wild strain. These imply that the gra-orf7gene did not play an important role in morphological development, differentiation and granaticin biosynthetic process of S vietnamensis. However, the delay phenomenon of producing granaticin in the mutant, that was directly related to the inactivation of gra-orf7gene。Consequently, these indicate that the gra-orf7gene had a certain biological function, it may be involved in signal transduction of the upstream regulation of granaticin biosynthesis in S.vietnamensis, and may also be the targeting protein of gra-orf7gene that would be activated by other unknown STPK, to form some sort of compensatory mechanism. |
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