1s77
From Proteopedia
T7 RNAP product pyrophosphate elongation complex
Structural highlights
Function[RPOL_BPT7] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Responsible for the transcription of the late genes of T7. It is rifampicin-resistant. It recognizes a specific promoter sequence, unwinds the double-stranded RNA to expose the coding strand for templating, initiates transcription preferentially with a purine. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedRNA polymerase functions like a molecular motor that can convert chemical energy into the work of strand separation and translocation along the DNA during transcription. The structures of phage T7 RNA polymerase in an elongation phase substrate complex that includes the incoming nucleoside triphosphate and a pretranslocation product complex that includes the product pyrophosphate (PPi) are described here. These structures and the previously determined posttranslocation elongation complex demonstrate that two enzyme conformations exist during a cycle of single nucleotide addition. One orientation of a five-helix subdomain is stabilized by the phosphates of either the incoming NTP or by the product PPi. A second orientation of this subdomain is stable in their absence and is associated with translocation of the heteroduplex product as well as strand separation of the downstream DNA. We propose that the dissociation of the product PPi after nucleotide addition produces the protein conformational change resulting in translocation and strand separation. The structural mechanism of translocation and helicase activity in T7 RNA polymerase.,Yin YW, Steitz TA Cell. 2004 Feb 6;116(3):393-404. PMID:15016374[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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