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| {{STRUCTURE_1qyp| PDB=1qyp | SCENE= }} | | {{STRUCTURE_1qyp| PDB=1qyp | SCENE= }} |
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| '''THERMOCOCCUS CELER RPB9, NMR, 25 STRUCTURES'''
| | ===THERMOCOCCUS CELER RPB9, NMR, 25 STRUCTURES=== |
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| ==Overview==
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| BACKGROUND: Transcriptional initiation and elongation provide control points in gene expression. Eukaryotic RNA polymerase II subunit 9 (RPB9) regulates start-site selection and elongational arrest. RPB9 contains Cys4 Zn(2+)-binding motifs which are conserved in archaea and homologous to those of the general transcription factors TFIIB and TFIIS. RESULTS: The structure of an RPB9 domain from the hyperthermophilic archaeon Thermococcus celer was determined at high resolution by NMR spectroscopy. The structure consists of an apical tetrahedral Zn(2+)-binding site, central beta sheet and disordered loop. Although the structure lacks a globular hydrophobic core, the two surfaces of the beta sheet each contain well ordered aromatic rings engaged in serial edge-to-face interactions. Basic sidechains are clustered near the Zn(2+)-binding site. The disordered loop contains sidechains conserved in TFIIS, including acidic residues essential for the stimulation of transcriptional elongation. CONCLUSIONS: The planar architecture of the RPB9 zinc ribbon-distinct from that of a conventional globular domain-can accommodate significant differences in the alignment of polar, non-polar and charged sidechains. Such divergence is associated with local and non-local changes in structure. The RPB9 structure is distinguished by a fourth beta strand (extending the central beta sheet) in a well ordered N-terminal segment and also differs from TFIIS (but not TFIIB) in the orientation of its apical Zn(2+)-binding site. Cys4 Zn(2+)-binding sites with distinct patterns of polar, non-polar and charged residues are conserved among unrelated RNAP subunits and predicted to form variant zinc ribbons.
| | The line below this paragraph, {{ABSTRACT_PUBMED_9634694}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 9634694 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_9634694}} |
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| ==About this Structure== | | ==About this Structure== |
| 1QYP is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Thermococcus_celer Thermococcus celer]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QYP OCA]. | | 1QYP is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Thermococcus_celer Thermococcus celer]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QYP OCA]. |
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| ==Reference== | | ==Reference== |
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| [[Category: Transcription]] | | [[Category: Transcription]] |
| [[Category: Zn ribbon]] | | [[Category: Zn ribbon]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 06:51:53 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 29 08:00:13 2008'' |
