期刊
JOURNAL OF BIOLOGICAL CHEMISTRY
卷 278, 期 18, 页码 16443-16450出版社
AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
DOI: 10.1074/jbc.M211267200
关键词
-
资金
- PHS HHS [G, 45404] Funding Source: Medline
In a previous study (Dubbs, J. M., Bird, T. H., Bauer, C. E., and Tabita, F. R. (2000) J. Biol. Chem 275,1922419230), it was demonstrated that the regulators CbbR and RegA (PrrA) interacted with both promoter proximal and promoter distal regions of the form I (ebb,) promoter operon specifying genes of the Calvin-Benson-Bassham cycle of Rhodobacter sphaeroides. To determine how these regulators interact with the form II (ebb,,) promoter, three cbbF(II:):lacZ translational fusion plasmids were constructed containing various lengths of sequence 5' to the cbb(II) operon of R. sphaeroides CAC. Expression of beta-galactosidase was monitored under a variety of growth conditions in both the parental strain and knock-out strains that contain mutations that affect synthesis of CbbR and RegA. The binding sites for both CbbR and RegA were determined by DNase I footprinting. A region of the cbb(II) promoter from +38 to -227 bp contained a CbbR binding site and conferred low level regulated cbb(II) expression. The region from -227 to -1025 bp contained six RegA binding sites and conferred enhanced cbb(II) expression under all growth conditions. Unlike the cbb(I) operon, the region between -227 and -545 bp that contains one RegA binding site, was responsible for the majority of the observed enhancement. Both RegA and CbbR were required for maximal cbb(II) expression. Two potentially novel and specific cbb(II) promoter-binding proteins that did not interact with the cbb(I) promoter region were detected in crude extracts of R. sphaeroides. These results, combined with the observation that chemoautotrophic expression of the cbb(I) operon is RegA independent, indicated that the mechanisms controlling cbb(I) and cbb(II) operon expression during chemoautotrophic growth are quite different.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据