1tlh
From Proteopedia
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| Gene: | ASIA (Bacteriophage T4), RPOD, ALT, B3067 (Escherichia coli) | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
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
Page seeded by OCA on Thu Mar 20 14:19:59 2008
