1tty
From Proteopedia
(New page: 200px<br /><applet load="1tty" size="450" color="white" frame="true" align="right" spinBox="true" caption="1tty" /> '''Solution structure of sigma A region 4 from ...) |
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'''Solution structure of sigma A region 4 from Thermotoga maritima'''<br /> | '''Solution structure of sigma A region 4 from Thermotoga maritima'''<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== | ||
| - | 1TTY is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermotoga_maritima Thermotoga maritima]. Full crystallographic information is available from [http:// | + | 1TTY is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Thermotoga_maritima Thermotoga maritima]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1TTY OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Thermotoga maritima]] | [[Category: Thermotoga maritima]] | ||
[[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: helix-turn-helix]] | [[Category: helix-turn-helix]] | ||
[[Category: rna polymerase]] | [[Category: rna polymerase]] | ||
[[Category: sigma factor]] | [[Category: sigma factor]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:17:17 2008'' |
Revision as of 13:17, 21 February 2008
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Solution structure of sigma A region 4 from Thermotoga maritima
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
1TTY is a Single protein structure of sequence from Thermotoga maritima. 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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