6kj6
From Proteopedia
cryo-EM structure of Escherichia coli Crl transcription activation complex
Structural highlights
Function[RPOC_ECOLI] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates.[HAMAP-Rule:MF_01322] [CRL_ECOLC] Binds to the sigma-S subunit of RNA polymerase, activating expression of sigma-S-regulated genes. Stimulates RNA polymerase holoenzyme formation and may bind to several other sigma factors, such as sigma-70 and sigma-32. [RPOB_ECOLI] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates.[HAMAP-Rule:MF_01321] [RPOA_ECOLI] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. This subunit plays an important role in subunit assembly since its dimerization is the first step in the sequential assembly of subunits to form the holoenzyme.[HAMAP-Rule:MF_00059] [RPOZ_ECOLI] Promotes RNA polymerase assembly. Latches the N- and C-terminal regions of the beta' subunit thereby facilitating its interaction with the beta and alpha subunits.[HAMAP-Rule:MF_00366] [RPOS_ECOLI] Sigma factors are initiation factors that promote the attachment of RNA polymerase to specific initiation sites and are then released. This sigma factor is the master transcriptional regulator of the stationary phase and the general stress response. Controls, positively or negatively, the expression of several hundred genes, which are mainly involved in metabolism, transport, regulation and stress management.[HAMAP-Rule:MF_00959][1] [2] [3] [4] [5] Protects stationary phase cells from killing induced by endoribonuclease MazF.[6] Publication Abstract from PubMedsigma(S) is a master transcription initiation factor that protects bacterial cells from various harmful environmental stresses including antibiotic pressure. Although its mechanism remains unclear, it is known that full activation of sigma(S)-mediated transcription requires a sigma(S)-specific activator, Crl. In this study, we determined a 3.80 A cryo-EM structure of an Escherichia coli transcription activation complex (E. coli Crl-TAC) comprising E. coli sigma(S)-RNA polymerase (sigma(S)-RNAP) holoenzyme, Crl, and a nucleic-acid scaffold. The structure reveals that Crl interacts with domain 2 of sigma(S) (sigma(S)2) and the RNAP core enzyme, but does not contact promoter DNA. Results from subsequent hydrogen-deuterium exchange mass spectrometry (HDX-MS) indicate that Crl stabilizes key structural motifs within sigma(S)2 to promote the assembly of the sigma(S)-RNAP holoenzyme and also to facilitate formation of an RNA polymerase-promoter DNA open complex (RPo). Our study demonstrates a unique DNA contact-independent mechanism of transcription activation, thereby defining a previously unrecognized mode of transcription activation in cells. Crl activates transcription by stabilizing active conformation of the master stress transcription initiation factor.,Xu J, Cui K, Shen L, Shi J, Li L, You L, Fang C, Zhao G, Feng Y, Yang B, Zhang Y Elife. 2019 Dec 17;8. pii: 50928. doi: 10.7554/eLife.50928. PMID:31846423[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
| ||||||||||||||||||||
