Database accession: MF7000714
Name: V66A/L68V CzrA with Zn
PDB ID: 4ggg
Experimental method: X-ray (2.00 Å)
Assembly: Homodimer
Source organism: Staphylococcus aureus
Primary publication of the structure:
Campanello GC, Ma Z, Grossoehme NE, Guerra AJ, Ward BP, Dimarchi RD, Ye Y, Dann CE, Giedroc DP
Allosteric inhibition of a zinc-sensing transcriptional repressor: insights into the arsenic repressor (ArsR) family.
(2013) J. Mol. Biol. 425: 1143-57
PMID: 23353829
Abstract:
The molecular basis of allosteric regulation remains a subject of intense interest. Staphylococcus aureus CzrA is a member of the ubiquitous arsenic repressor (ArsR) family of bacterial homodimeric metal-sensing proteins and has emerged as a model system for understanding allosteric regulation of operator DNA binding by transition metal ions. Using unnatural amino acid substitution and a standard linkage analysis, we show that a His97' NH(ε2)...O=C His67 quaternary structural hydrogen bond is an energetically significant contributor to the magnitude of the allosteric coupling free energy, ∆Gc. A "cavity" introduced just beneath this hydrogen bond in V66A/L68V CzrA results in a significant reduction in regulation by Zn(II) despite adopting a wild-type global structure and Zn(II) binding and DNA binding affinities only minimally affected from wild type. The energetics of Zn(II) binding and heterotropic coupling free energies (∆Hc, -T∆Sc) of the double mutant are also radically altered and suggest that increased internal dynamics leads to poorer allosteric negative regulation in V66A/L68V CzrA. A statistical coupling analysis of 3000 ArsR proteins reveals a sector that links the DNA-binding determinants and the α5 Zn(II)-sensing sites through V66/L68 in CzrA. We propose that distinct regulatory sites uniquely characteristic of individual ArsR proteins result from evolution of distinct connectivities to this sector, each capable of driving the same biological outcome, transcriptional derepression.
Annotations from the GeneOntology database. Only terms that fit at least two of the interacting proteins are shown. Molecular function:
DNA binding DNA binding
DNA-binding transcription factor activity DNA-binding transcription factor activity
metal ion binding metal ion binding
Biological process: not assigned
Cellular component: not assigned
Structural annotations of the participating protein chains.Entry contents: 2 distinct polypeptide molecules
Chains: A, A-2
Notes: All chains according to the most probable oligomerization state stored in PDBe were considered.
Number of unique protein segments: 1
Name: Repressor protein
Source organism: Staphylococcus aureus
Length: 106 residues
Sequence:Sequence according to the corresponding UniProt protein segmentMSEQYSEINTDTLERVTEIFKALGDYNRIRIMELLSVSEASVGHISHQLNLSQSNVSHQLKLLKSVHLVKAKRQGQSMIYSLDDIHVATMLKQAIHHANHPKESGL
UniProtKB AC: A0A0H3JNF1 (positions: 11-102)
Coverage: 86%
Name: Repressor protein
Source organism: Staphylococcus aureus
Length: 106 residues
Sequence:Sequence according to the corresponding UniProt protein segmentMSEQYSEINTDTLERVTEIFKALGDYNRIRIMELLSVSEASVGHISHQLNLSQSNVSHQLKLLKSVHLVKAKRQGQSMIYSLDDIHVATMLKQAIHHANHPKESGL
UniProtKB AC: A0A0H3JNF1 (positions: 9-101)
Coverage: 87%
Evidence demonstrating that the participating proteins are unstructured prior to the interaction and their folding is coupled to binding. Representative domain in related structures: Winged helix DNA-binding domain (ArsR family) transcriptional regulator
Evidence level: Indirect evidence
Evidence coverage: Only some parts of the structure participates in mutual synergistic folding.
Complex Evidence:
The N-terminal portion of the ArsR family transcriptional regulator, Mj223, is a helix-turn-helix (HTH) winged-helix DNA-binding motif. The C-terminal region of the protein is composed of two leucine-rich α-helices (H5 and H6) that form an antiparallel four-helix bundle with a large, hydrophobic interaction surface on dimerization that forms the hydrophobic core of the dimer (PMID:12471609, PMID:9466913). The C-terminal dimerization subdomain is a nice case of MSF. The protein is a dimer in solution (Dynamic light scattering) (PMID:12471609).
Chain A:
N/A
Chain A-2:
N/A
Surface and contacts features:
Structures from the PDB that contain the same number of proteins, and the proteins from the two structures show a sufficient degree of pairwise similarity, i.e. they belong to the same UniRef90 cluster (the full proteins exhibit at least 90% sequence identity) and convey roughly the same region to their respective interactions (the two regions from the two proteins share a minimum of 70% overlap). Download the CIF file (.cif)
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