4igc
From Proteopedia
X-ray crystal structure of Escherichia coli sigma70 holoenzyme
Structural highlights
Function[H0QDQ9_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 (By similarity).[HAMAP-Rule:MF_00366][SAAS:SAAS003716_004_017283] [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] [RPOC_ECOLI] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates.[HAMAP-Rule:MF_01322] [RPOB_ECOLI] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates.[HAMAP-Rule:MF_01321] [RPOD_ECOLI] Sigma factors are initiation factors that promote the attachment of RNA polymerase to specific initiation sites and are then released. This is the primary sigma factor of this bacterium. Publication Abstract from PubMedEscherichia coli RNA polymerase (RNAP) is the most studied bacterial RNAP and has been used as the model RNAP for screening and evaluating potential RNAP-targeting antibiotics. However, the x-ray crystal structure of E. coli RNAP has been limited to individual domains. Here, I report the x-ray structure of the E. coli RNAP sigma(70) holoenzyme, which shows sigma region 1.1 (sigma1.1) and the alpha subunit C-terminal domain for the first time in the context of an intact RNAP. sigma1.1 is positioned at the RNAP DNA-binding channel and completely blocks DNA entry to the RNAP active site. The structure reveals that sigma1.1 contains a basic patch on its surface, which may play an important role in DNA interaction to facilitate open promoter complex formation. The alpha subunit C-terminal domain is positioned next to sigma domain 4 with a fully stretched linker between the N- and C-terminal domains. E. coli RNAP crystals can be prepared from a convenient overexpression system, allowing further structural studies of bacterial RNAP mutants, including functionally deficient and antibiotic-resistant RNAPs. X-ray crystal structure of Escherichia coli RNA polymerase sigma70 holoenzyme.,Murakami KS J Biol Chem. 2013 Mar 29;288(13):9126-34. doi: 10.1074/jbc.M112.430900. Epub 2013, Feb 6. PMID:23389035[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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