1CEZ

CRYSTAL STRUCTURE OF A T7 RNA POLYMERASE-T7 PROMOTER COMPLEX

Summary for 1CEZ

• Entry DOI: 10.2210/pdb1cez/pdb
• Descriptor: DNA (5'-D(P*TP*AP*TP*AP*GP*TP*GP*AP*GP*TP*CP*GP*TP*AP*TP*TP*A)-3'), DNA (5'-D(P*TP*AP*AP*TP*AP*CP*GP*AP*CP*TP*CP*AP*CP*TP*A)-3'), PROTEIN (BACTERIOPHAGE T7 RNA POLYMERASE), ... (4 entities in total)
• Functional Keywords: t7 rna polymerase, transferase-dna complex, transferase/dna
• Biological source: Enterobacteria phage T7
• Total number of polymer chains: 3
• Total formula weight: 108777.65

Authors

Cheetham, G.M.T.,Jeruzalmi, D.,Steitz, T.A. (deposition date: 1999-03-11, release date: 1999-05-21, Last modification date: 2023-12-27)

Primary citation

Cheetham, G.M.,Jeruzalmi, D.,Steitz, T.A.
Structural basis for initiation of transcription from an RNA polymerase-promoter complex.
Nature, 399:80-83, 1999

PubMed Abstract: 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.

PubMed: 10331394
DOI: 10.1038/19999

Experimental method

X-RAY DIFFRACTION (2.4 Å)