Sequence Analysis and Functional Expression of the Structural and Regulatory Genes for Pyruvate Dehydrogenase Complex from Streptomyces seoulensis

다국어 초록 (Multilingual Abstract)

A cluster of genes encoding the pyruvate dehydrogenase complex (PDC) of Streptomyces seoulensis, a
Gram-positive bacterium, was cloned and sequenced. The genes of S. seoulensis consist of four open
reading frames. The first gene, lpd, which encodes a lipoamide dehydrogenase, is followed by pdhB
encoding a dihydrolipoamide acetyltransferase (E2p), pdhR, a regulatory gene, and pdhA encoding a
pyruvate dehydrogenase component (E1p). E1p had an unusual homodimeric subunit, which has been
known only in Gram-negative bacteria. S. seoulensis E2p contains two lipoyl domains like those of
humans and Streptococcus faecalis. The pdhR gene appears to be clustered with the structural genes
of S. seoulensis PDC. The PdhR-overexpressed S. seoulensis showed growth retardation and the
decrease of E1p, indicating that PdhR regulates the function of PDC by repressing the expression of
E1p. A strain of Streptomyces lividans overexpressing S. seoulensis PdhR showed a significant decrease
in the level of actinorhodin, implying a regulatory role for Streptomyces PDC in antibiotic biosynthesis.