Exceptional characteristics of heterotetrameric (alpha(2)beta(2)) E1p of the pyruvate dehydrogenase complex from Zymomonas mobilis: expression from an own promoter and a lipoyl domain in E1 beta

In the pyruvate dehydrogenase complex (PDHC) of Zymomonas mobilis the beta subunit of the pyruvate dehydrogenase (E1p) as well as the acetyltransferas e (E2p) contain an N-terminal lipoyl domain. Both lipoyl domains were acety lated in vitro using 2-C-14-pyruvate as a substrate, demonstrating that bot h lipoyl domains can accept acetyl groups from the E1 component. As previou sly shown the structural genes (pdhA alpha beta, pdhB, lpd) encoding the py ruvate dehydrogenase complex of Z. mobilis are located in two distinct gene clusters, pdhA alpha beta and pdhB-orf2-lpd (U. Neveling et al. (1998) J. Bacteriol. 180, 1540-1548). Analysis of pdh gene expression using lacZ fusi ons revealed that the DNA fragments upstream of pdhA alpha, pdhB and lpd ea ch have promoter activities. These pdh promoter activities were 7-30-fold h igher in Z. mobilis than in Escherichia coli. (C) 1999 Federation of Europe an Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.