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From Proteopedia
T. thermophilus RNA polymerase holoenzyme bound with gp39 and gp76
Structural highlights
Function[RPOZ_THET8] 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). [RPOA_THET8] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. [RPOC_THET8] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. [RPOB_THET8] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. [Q5SKW1_THET8] Sigma factors are initiation factors that promote the attachment of RNA polymerase to specific initiation sites and are then released (By similarity).[RuleBase:RU000715] 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 primary sigma factor during exponential growth (By similarity).[HAMAP-Rule:MF_00963] Publication Abstract from PubMedRNA polymerase (RNAP) is a major target of gene regulation. Thermus thermophilus bacteriophage P23-45 encodes two RNAP binding proteins, gp39 and gp76, which shut off host gene transcription while allowing orderly transcription of phage genes. We previously reported the structure of the T. thermophilus RNAP*sigmaA holoenzyme complexed with gp39. Here, we solved the structure of the RNAP*sigmaA holoenzyme bound with both gp39 and gp76, which revealed an unprecedented inhibition mechanism by gp76. The acidic protein gp76 binds within the RNAP cleft and occupies the path of the template DNA strand at positions -11 to -4, relative to the transcription start site at +1. Thus, gp76 obstructs the formation of an open promoter complex and prevents transcription by T. thermophilus RNAP from most host promoters. gp76 is less inhibitory for phage transcription, as tighter RNAP interaction with the phage promoters allows the template DNA to compete with gp76 for the common binding site. gp76 also inhibits Escherichia coli RNAP highlighting the template-DNA binding site as a new target site for developing antibacterial agents. A Thermus phage protein inhibits host RNA polymerase by preventing template DNA strand loading during open promoter complex formation.,Ooi WY, Murayama Y, Mekler V, Minakhin L, Severinov K, Yokoyama S, Sekine SI Nucleic Acids Res. 2017 Nov 20. pii: 4641909. doi: 10.1093/nar/gkx1162. PMID:29165680[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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