Structure of a T7 RNA polymerase elongation complex at 2.9 Å resolution

• Published in: Nature (London) Vol. 420; no. 6911; pp. 43 - 50
• Main Authors: Vassylyev, Dmitry G, Yokoyama, Shigeyuki, Tahirov, Tahir H, Temiakov, Dmitry, Anikin, Michael, Patlan, Vsevolod, McAllister, William T
• Format: Journal Article
• Language: English
• Published: London Nature Publishing 07.11.2002; Nature Publishing Group
• Subjects: Amino Acid Sequence; Bacteriophage T7 - enzymology; Base Pairing; Binding Sites; Biological and medical sciences; Crystalline structure; Crystallography, X-Ray; DNA - genetics; DNA - metabolism; DNA-Directed RNA Polymerases - chemistry; DNA-Directed RNA Polymerases - metabolism; Fundamental and applied biological sciences. Psychology; Models, Molecular; Molecular and cellular biology; Molecular biophysics; Molecular genetics; Molecular Sequence Data; Promoter Regions, Genetic; Protein Binding; Protein Folding; Protein Structure, Tertiary; RNA - biosynthesis; RNA - genetics; RNA - metabolism; Static Electricity; Structure in molecular biology; Transcription, Genetic; Transcription. Transcription factor. Splicing. Rna processing; Viral Proteins; Virus; Nucleotidyltransferases; High resolution; Enzyme; Podoviridae; Transferases; Phage T7; Complexes; DNA-directed RNA polymerase; Elongation; Phage; Crystalline structure
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature01129

The single-subunit bacteriophage T7 RNA polymerase carries out the transcription cycle in an identical manner to that of bacterial and eukaryotic multisubunit enzymes. Here we report the crystal structure of a T7 RNA polymerase elongation complex, which shows that incorporation of an 8-base-pair RNA-DNA hybrid into the active site of the enzyme induces a marked rearrangement of the amino-terminal domain. This rearrangement involves alternative folding of about 130 residues and a marked reorientation (about 130 degrees rotation) of a stable core subdomain, resulting in a structure that provides elements required for stable transcription elongation. A wide opening on the enzyme surface that is probably an RNA exit pathway is formed, and the RNA-DNA hybrid is completely buried in a newly formed, deep protein cavity. Binding of 10 base pairs of downstream DNA is stabilized mostly by long-distance electrostatic interactions. The structure implies plausible mechanisms for the various phases of the transcription cycle, and reveals important structural similarities with the multisubunit RNA polymerases.