1SMT

SMTB REPRESSOR FROM SYNECHOCOCCUS PCC7942


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.217 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Crystal structure of the cyanobacterial metallothionein repressor SmtB: a model for metalloregulatory proteins.

Cook, W.J.Kar, S.R.Taylor, K.B.Hall, L.M.

(1998) J.Mol.Biol. 275: 337-346

  • DOI: 10.1006/jmbi.1997.1443

  • PubMed Abstract: 
  • 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 ...

    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.


    Organizational Affiliation

    Department of Pathology, University of Alabama at Birmingham 35294, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
TRANSCRIPTIONAL REPRESSOR SMTB
A, B
122Synechococcus elongatus (strain PCC 7942)Mutation(s): 0 
Gene Names: smtB
Find proteins for P30340 (Synechococcus elongatus (strain PCC 7942))
Go to UniProtKB:  P30340
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.217 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 37.600α = 90.00
b = 70.900β = 95.70
c = 44.000γ = 90.00
Software Package:
Software NamePurpose
XENGENdata scaling
XENGENdata reduction
X-PLORmodel building
X-PLORrefinement
X-PLORphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 1997-09-16 
  • Released Date: 1997-12-03 
  • Deposition Author(s): Cook, W.J., Hall, L.M.

Revision History 

  • Version 1.0: 1997-12-03
    Type: Initial release
  • Version 1.1: 2008-03-24
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Source and taxonomy, Version format compliance