1tlh
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'''T4 AsiA bound to sigma70 region 4'''<br /> | '''T4 AsiA bound to sigma70 region 4'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Bacteriophage T4 AsiA is a versatile transcription factor capable of | + | Bacteriophage T4 AsiA is a versatile transcription factor capable of inhibiting host gene expression as an 'anti-sigma' factor while simultaneously promoting gene-specific expression of T4 middle genes in conjunction with T4 MotA. To accomplish this task, AsiA engages conserved region 4 of Eschericia coli sigma70, blocking recognition of most host promoters by sequestering the DNA-binding surface at the AsiA/sigma70 interface. The three-dimensional structure of an AsiA/region 4 complex reveals that the C-terminal alpha helix of region 4 is unstructured, while four other helices adopt a completely different conformation relative to the canonical structure of unbound region 4. That AsiA induces, rather than merely stabilizes, this rearrangement can be realized by comparison to the homologous structures of region 4 solved in a variety of contexts, including the structure of Thermotoga maritima sigmaA region 4 described herein. AsiA simultaneously occupies the surface of region 4 that ordinarily contacts core RNA polymerase (RNAP), suggesting that an AsiA-bound sigma70 may also undergo conformational changes in the context of the RNAP holoenzyme. |
==About this Structure== | ==About this Structure== | ||
| - | 1TLH is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Bacteriophage_t4 Bacteriophage t4] and [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http:// | + | 1TLH is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Bacteriophage_t4 Bacteriophage t4] and [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1TLH OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Protein complex]] | [[Category: Protein complex]] | ||
[[Category: Demeler, B.]] | [[Category: Demeler, B.]] | ||
| - | [[Category: Lambert, L | + | [[Category: Lambert, L J.]] |
[[Category: Schirf, V.]] | [[Category: Schirf, V.]] | ||
[[Category: Wei, Y.]] | [[Category: Wei, Y.]] | ||
| - | [[Category: Werner, M | + | [[Category: Werner, M H.]] |
[[Category: anti-sigma]] | [[Category: anti-sigma]] | ||
[[Category: nmr]] | [[Category: nmr]] | ||
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[[Category: sigma70]] | [[Category: sigma70]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:14:46 2008'' |
Revision as of 13:14, 21 February 2008
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T4 AsiA bound to sigma70 region 4
Overview
Bacteriophage T4 AsiA is a versatile transcription factor capable of inhibiting host gene expression as an 'anti-sigma' factor while simultaneously promoting gene-specific expression of T4 middle genes in conjunction with T4 MotA. To accomplish this task, AsiA engages conserved region 4 of Eschericia coli sigma70, blocking recognition of most host promoters by sequestering the DNA-binding surface at the AsiA/sigma70 interface. The three-dimensional structure of an AsiA/region 4 complex reveals that the C-terminal alpha helix of region 4 is unstructured, while four other helices adopt a completely different conformation relative to the canonical structure of unbound region 4. That AsiA induces, rather than merely stabilizes, this rearrangement can be realized by comparison to the homologous structures of region 4 solved in a variety of contexts, including the structure of Thermotoga maritima sigmaA region 4 described herein. AsiA simultaneously occupies the surface of region 4 that ordinarily contacts core RNA polymerase (RNAP), suggesting that an AsiA-bound sigma70 may also undergo conformational changes in the context of the RNAP holoenzyme.
About this Structure
1TLH is a Protein complex structure of sequences from Bacteriophage t4 and Escherichia coli. Full crystallographic information is available from OCA.
Reference
T4 AsiA blocks DNA recognition by remodeling sigma70 region 4., Lambert LJ, Wei Y, Schirf V, Demeler B, Werner MH, EMBO J. 2004 Aug 4;23(15):2952-62. Epub 2004 Jul 15. PMID:15257291
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