Nussbaum-Shochat A, Amster-Choder O
Department of Molecular Biology, Hebrew University-Hadassah Medical School, P.O.Box 12272, Jerusalem 91120, Israel.
Proc Natl Acad Sci U S A. 1999 Apr 13;96(8):4336-41. doi: 10.1073/pnas.96.8.4336.
The Escherichia coli BglG protein antiterminates transcription at two terminator sites within the bgl operon in response to the presence of beta-glucosides in the growth medium. BglG was previously shown to be an RNA-binding protein that recognizes a specific sequence located just upstream of each of the terminators and partially overlapping with them. We show here that BglG also binds to the E. coli RNA polymerase, both in vivo and in vitro. By using several techniques, we identified the beta' subunit of RNA polymerase as the target for BglG binding. The region that contains the binding site for BglG was mapped to the N-terminal region of beta'. The beta' subunit, produced in excess, prevented BglG activity as a transcriptional antiterminator. Possible roles of the interaction between BglG and the polymerase beta' subunit are discussed.
大肠杆菌BglG蛋白可响应生长培养基中β-葡萄糖苷的存在，在bgl操纵子内的两个终止子位点处抗终止转录。先前已证明BglG是一种RNA结合蛋白，可识别位于每个终止子上游且与之部分重叠的特定序列。我们在此表明，BglG在体内和体外均能与大肠杆菌RNA聚合酶结合。通过多种技术，我们确定RNA聚合酶的β'亚基是BglG结合的靶点。包含BglG结合位点的区域被定位到β'的N端区域。过量产生的β'亚基会阻止BglG作为转录抗终止子的活性。文中讨论了BglG与聚合酶β'亚基之间相互作用的可能作用。
