2KJB image
Deposition Date 2009-05-27
Release Date 2009-11-10
Last Version Date 2024-05-22
Entry Detail
PDB ID:
2KJB
Title:
Solution structure of CzrA in the DNA bound state
Biological Source:
Source Organism:
Host Organism:
Method Details:
Experimental Method:
Conformers Calculated:
100
Conformers Submitted:
21
Selection Criteria:
structures with the least restraint violations
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:CzrA protein
Gene (Uniprot):rzcA
Chain IDs:A, B
Chain Length:106
Number of Molecules:2
Biological Source:Staphylococcus aureus
Ligand Molecules
Primary Citation
Solution structure of a paradigm ArsR family zinc sensor in the DNA-bound state
Proc.Natl.Acad.Sci.USA 106 18177 18182 (2009)
PMID: 19822742 DOI: 10.1073/pnas.0905558106

Abstact

Staphylococcus aureus CzrA is a zinc-dependent transcriptional repressor from the ubiquitous ArsR family of metal sensor proteins. Zn(II) binds to a pair of intersubunit C-terminal alpha5-sensing sites, some 15 A distant from the DNA-binding interface, and allosterically inhibits DNA binding. This regulation is characterized by a large allosteric coupling free energy (DeltaGc) of approximately +6 kcal mol(-1), the molecular origin of which is poorly understood. Here, we report the solution quaternary structure of homodimeric CzrA bound to a palindromic 28-bp czr operator, a structure that provides an opportunity to compare the two allosteric "end" states of an ArsR family sensor. Zn(II) binding drives a quaternary structural switch from a "closed" DNA-binding state to a low affinity "open" conformation as a result of a dramatic change in the relative orientations of the winged helical DNA binding domains within the dimer. Zn(II) binding also effectively quenches both rapid and intermediate timescale internal motions of apo-CzrA while stabilizing the native state ensemble. In contrast, DNA binding significantly enhances protein motions in the allosteric sites and reduces the stability of the alpha5 helices as measured by H-D solvent exchange. This study reveals how changes in the global structure and dynamics drive a long-range allosteric response in a large subfamily of bacterial metal sensor proteins, and provides insights on how other structural classes of ArsR sensor proteins may be regulated by metal binding.

Legend

Protein

Chemical

Disease

Primary Citation of related structures