원문정보
초록
영어
Tautomycetin (TMC) is a novel activated T cell – specific immunosuppressive compound with an
ester bond linkage between a terminal cyclic anhydride moiety and a linear polyketide chain bearing an unusual terminal alkene. The presence of a 1.5kb gene of tmcC, whose deduced product was found to have some amino acid sequence homology with previously-known bacterial esterase, was found just upstream of tmc PKS genes in an approximately 70-kb contiguous TMC biosynthetic gene cluster. In silico database comparisons revealed that tmcC belongs to the type B carboxylesterase.
PCR-targeted disruption of the putative TMC-specific esterase gene, tmcC completely abolished TMC biosynthesis. As expected, complementation by tmcC integratation into the mutant chromosome restored TMC biosynthesis. Moreover, the codon-optimzed tmcC was also over-expressed as a Histagged fusion protein in E. coli, followed by the in vitro biochemical esterase assays. Taken together, these data provide strong supporting evidence that the tmcC encodes a putative TMC-specific esterase, which plays a critical role in TMC biosynthesis in Streptomyces sp. CK4412.