Minakhin L, Bhagat S, Brunning A, Campbell E A, Darst S A, Ebright R H, Severinov K
Waksman Institute, Department of Genetics, Department of Chemistry and Howard Hughes Medical Institute, Rutgers, The State University, Piscataway, NJ 08854, USA.
Proc Natl Acad Sci U S A. 2001 Jan 30;98(3):892-7. doi: 10.1073/pnas.98.3.892.
Bacterial DNA-dependent RNA polymerase (RNAP) has subunit composition beta'betaalpha(I)alpha(II)omega. The role of omega has been unclear. We show that omega is homologous in sequence and structure to RPB6, an essential subunit shared in eukaryotic RNAP I, II, and III. In Escherichia coli, overproduction of omega suppresses the assembly defect caused by substitution of residue 1362 of the largest subunit of RNAP, beta'. In yeast, overproduction of RPB6 suppresses the assembly defect caused by the equivalent substitution in the largest subunit of RNAP II, RPB1. High-resolution structural analysis of the omega-beta' interface in bacterial RNAP, and comparison with the RPB6-RPB1 interface in yeast RNAP II, confirms the structural relationship and suggests a "latching" mechanism for the role of omega and RPB6 in promoting RNAP assembly.
细菌依赖DNA的RNA聚合酶(RNAP)具有β'βα(I)α(II)ω亚基组成。ω的作用一直不清楚。我们发现,ω在序列和结构上与真核生物RNAP I、II和III共有的必需亚基RPB6同源。在大肠杆菌中,ω的过量表达抑制了由RNAP最大亚基β'的1362位残基替代引起的组装缺陷。在酵母中,RPB6的过量表达抑制了由RNAP II最大亚基RPB1中的等效替代引起的组装缺陷。对细菌RNAP中ω-β'界面的高分辨率结构分析,以及与酵母RNAP II中RPB6-RPB1界面的比较,证实了结构关系,并提出了一种ω和RPB6在促进RNAP组装中作用的“锁定”机制。