1smt
From Proteopedia
OCA (Talk | contribs)
(New page: 200px<br /><applet load="1smt" size="450" color="white" frame="true" align="right" spinBox="true" caption="1smt, resolution 2.2Å" /> '''SMTB REPRESSOR FROM S...)
Next diff →
Revision as of 00:22, 21 November 2007
|
SMTB REPRESSOR FROM SYNECHOCOCCUS PCC7942
Overview
SmtB from Synechococcus PCC7942 is a trans-acting dimeric repressor that, is required for Zn(2+)-responsive expression of the metallothionein SmtA., The structure of SmtB was solved using multiple isomorphous replacement, techniques and refined at 2.2 A resolution by simulated annealing to an, R-factor of 0.218. SmtB displays the classical helix-turn-helix motif, found in many DNA-binding proteins. It has an alpha + beta topology, and, the arrangement of the three core helices and the beta hairpin is similar, to the HNF-3/fork head, CAP and diphtheria toxin repressor proteins., Although there is no zinc in the crystal structure, analysis of a mercuric, acetate derivative suggests a total of four Zn2+ binding sites in the, dimer. Two of these putative sites are at the opposite ends of the dimer, while the other two are at the dimer interface and are formed by residues, contributed from each monomer. The structure of the dimer is such that, simultaneous binding for both recognition helices to DNA would require, either a bend in the DNA helix or a conformational change in the dimer., The structure of Synechococcus SmtB is the first in this family of, metal-binding DNA repressors.
About this Structure
1SMT is a Single protein structure of sequence from Synechococcus sp.. Full crystallographic information is available from OCA.
Reference
Crystal structure of the cyanobacterial metallothionein repressor SmtB: a model for metalloregulatory proteins., Cook WJ, Kar SR, Taylor KB, Hall LM, J Mol Biol. 1998 Jan 16;275(2):337-46. PMID:9466913
Page seeded by OCA on Wed Nov 21 02:29:55 2007
