한빛사 논문
Abstract
Young-Ha Parka, Chang-Ro Leeb, Mangyu Choea, and Yeong-Jae Seoka,c,1
aDepartment of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 151-742, Korea;
bDepartment of Biological Sciences, Myongji University, Yongin, Gyeonggido 449-728, Korea; and
cDepartment of Biophysics and Chemical Biology, Seoul National University, Seoul 151-742, Korea
Abstract
The bacterial phosphoenolpyruvate:sugar phosphotransferase system (PTS) is a multicomponent system that participates in a variety of physiological processes in addition to the phosphorylation-coupled transport of numerous sugars. In Escherichia coli and other enteric bacteria, enzyme IIAGlc (EIIAGlc) is known as the central processing unit of carbon metabolism and plays multiple roles, including regulation of adenylyl cyclase, the fermentation/respiration switch protein FrsA, glycerol kinase, and several non-PTS transporters, whereas the only known regulatory role of the E. coli histidine-containing phosphocarrier protein HPr is in the activation of glycogen phosphorylase. Because HPr is known to be more abundant than EIIAGlc in enteric bacteria, we assumed that there might be more regulatory mechanisms connected with HPr. The ligand fishing experiment in this study identified Rsd, an anti-sigma factor known to complex with σ70 in stationary-phase cells, as an HPr-binding protein in E. coli. Only the dephosphorylated form of HPr formed a tight complex with Rsd and thereby inhibited complex formation between Rsd and σ70. Dephosphorylated HPr, but not phosphorylated HPr, antagonized the inhibitory effect of Rsd on σ70-dependent transcriptions both in vivo and in vitro, and also influenced the competition between σ70 and σS for core RNA polymerase in the presence of Rsd. Based on these data, we propose that the anti-σ70 activity of Rsd is regulated by the phosphorylation state-dependent interaction of HPr with Rsd.
glucose signaling, sigma factor competition, transcriptional regulation
1To whom correspondence should be addressed.
Author contributions: Y.-H.P. and Y.-J.S. designed research; Y.-H.P., C.-R.L., and M.C. performed research; Y.-H.P., C.-R.L., M.C., and Y.-J.S. analyzed data; and Y.-H.P., C.-R.L., and Y.-J.S. wrote the paper.
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