1cez

CRYSTAL STRUCTURE OF A T7 RNA POLYMERASE-T7 PROMOTER COMPLEX

spinqualitylabelsall models 1cez, resolution 2.40Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1cez is a 3 chain structure with sequence from Escherichia phage T7. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.4Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT 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 PubMed Although the single-polypeptide-chain RNA polymerase from bacteriophage T7 (T7RNAP), like other RNA polymerases, uses the same mechanism of polymerization as the DNA polymerases, it can also recognize a specific promoter sequence, initiate new RNA chains from a single nucleotide, abortively cycle the synthesis of short transcripts, be regulated by a transcription inhibitor, and terminate transcription. As T7RNAP is homologous to the Pol I family of DNA polymerases, the differences between the structure of T7RNAP complexed to substrates and that of the corresponding DNA polymerase complex provides a structural basis for understanding many of these functional differences. T7RNAP initiates RNA synthesis at promoter sequences that are conserved from positions -17 to +6 relative to the start site of transcription. The crystal structure at 2.4 A resolution of T7RNAP complexed with a 17-base-pair promoter shows that the four base pairs closest to the catalytic active site have melted to form a transcription bubble. The T7 promoter sequence is recognized by interactions in the major groove between an antiparallel beta-loop and bases. The amino-terminal domain is involved in promoter recognition and DNA melting. We have also used homology modelling of the priming and incoming nucleoside triphosphates from the T7 DNA-polymerase ternary complex structure to explain the specificity of T7RNAP for ribonucleotides, its ability to initiate from a single nucleotide, and the abortive cycling at the initiation of transcription. Structural basis for initiation of transcription from an RNA polymerase-promoter complex.,Cheetham GM, Jeruzalmi D, Steitz TA Nature. 1999 May 6;399(6731):80-3. PMID:10331394 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also RNA polymerase 3D structures

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