1pvo
From Proteopedia
X-ray crystal structure of Rho transcription termination factor in complex with ssRNA substrate and ANPPNP
Structural highlights
FunctionRHO_ECOLI Facilitates transcription termination by a mechanism that involves rho binding to the nascent RNA, activation of rho's RNA-dependent ATPase activity, and release of the mRNA from the DNA template. RNA-dependent NTPAse which utilizes all four ribonucleoside triphosphates as substrates.[HAMAP-Rule:MF_01884] 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 PubMedIn bacteria, one of the major transcriptional termination mechanisms requires a RNA/DNA helicase known as the Rho factor. We have determined two structures of Rho complexed with nucleic acid recognition site mimics in both free and nucleotide bound states to 3.0 A resolution. Both structures show that Rho forms a hexameric ring in which two RNA binding sites--a primary one responsible for target mRNA recognition and a secondary one required for mRNA translocation and unwinding--point toward the center of the ring. Rather than forming a closed ring, the Rho hexamer is split open, resembling a "lock washer" in its global architecture. The distance between subunits at the opening is sufficiently wide (12 A) to accommodate single-stranded RNA. This open configuration most likely resembles a state poised to load onto mRNA and suggests how related ring-shaped enzymes may be breached to bind nucleic acids. Structure of the Rho transcription terminator: mechanism of mRNA recognition and helicase loading.,Skordalakes E, Berger JM Cell. 2003 Jul 11;114(1):135-46. PMID:12859904[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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