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| - | [[Image:2pi5.gif|left|200px]] | + | {{Seed}} |
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| | {{STRUCTURE_2pi5| PDB=2pi5 | SCENE= }} | | {{STRUCTURE_2pi5| PDB=2pi5 | SCENE= }} |
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| - | '''T7 RNA polymerase complexed with a phi10 promoter'''
| + | ===T7 RNA polymerase complexed with a phi10 promoter=== |
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| - | ==Overview==
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| - | DNA-directed RNA polymerases are capable of initiating synthesis of RNA without primers, the first catalytic stage of initiation is referred to as de novo RNA synthesis. De novo synthesis is a unique phase in the transcription cycle where the RNA polymerase binds two nucleotides rather than a nascent RNA polymer and a single nucleotide. For bacteriophage T7 RNA polymerase, transcription begins with a marked preference for GTP at the +1 and +2 positions. We determined the crystal structures of T7 RNA polymerase complexes captured during the de novo RNA synthesis. The DNA substrates in the structures in the complexes contain a common Phi 10 duplex promoter followed by a unique five base single-stranded extension of template DNA whose sequences varied at positions +1 and +2, thereby allowing for different pairs of initiating nucleotides GTP, ATP, CTP or UTP to bind. The structures show that the initiating nucleotides bind RNA polymerase in locations distinct from those described previously for elongation complexes. Selection bias in favor of GTP as an initiating nucleotide is accomplished by shape complementarity, extensive protein side-chain and strong base-stacking interactions for the guanine moiety in the enzyme active site. Consequently, an initiating GTP provides the largest stabilization force for the open promoter conformation.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_17512007}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 17512007 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_17512007}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Initiating nucleoite]] | | [[Category: Initiating nucleoite]] |
| | [[Category: T7 rna polymerase]] | | [[Category: T7 rna polymerase]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 13:09:24 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 13:29:50 2008'' |
Revision as of 10:29, 28 July 2008
Template:STRUCTURE 2pi5
T7 RNA polymerase complexed with a phi10 promoter
Template:ABSTRACT PUBMED 17512007
About this Structure
2PI5 is a Single protein structure of sequence from Enterobacteria phage t7. Full crystallographic information is available from OCA.
Reference
Mechanism for de novo RNA synthesis and initiating nucleotide specificity by t7 RNA polymerase., Kennedy WP, Momand JR, Yin YW, J Mol Biol. 2007 Jul 6;370(2):256-68. Epub 2007 Mar 21. PMID:17512007
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