Nguyen L H, Jensen D B, Thompson N E, Gentry D R, Burgess R R
McArdle Laboratory for Cancer Research, University of Wisconsin-Madison 53706.
Biochemistry. 1993 Oct 19;32(41):11112-7. doi: 10.1021/bi00092a021.
The katF/rpoS gene product (sigma s), a central regulator of stationary-phase gene expression in Escherichia coli, has been purified from an overproducing strain. sigma s was used as an immunogen for the production of monoclonal antibodies. Previous sequence analysis of sigma s strongly indicated homology to the sigma factor family. We show biochemically in this paper that sigma s is a sigma factor. This protein can bind to core RNA polymerase (E), and this binding can be competed effectively by the major E. coli transcription initiation factor, sigma 70. Immunopurified sigma s holoenzyme (E sigma s) transcribes the promoters of the bolAp1 gene and the xthA gene. Interestingly, both promoters can also be transcribed by sigma 70 holoenzyme (E sigma 70).
katF/rpoS基因产物（σs）是大肠杆菌中稳定期基因表达的核心调节因子，已从高产菌株中纯化出来。σs被用作免疫原以制备单克隆抗体。先前对σs的序列分析强烈表明其与σ因子家族具有同源性。我们在本文中通过生化方法表明σs是一种σ因子。这种蛋白质可以与核心RNA聚合酶（E）结合，并且大肠杆菌主要转录起始因子σ70可以有效地竞争这种结合。免疫纯化的σs全酶（Eσs）可转录bolAp1基因和xthA基因的启动子。有趣的是，这两个启动子也可以被σ70全酶（Eσ70）转录。
