Solution structure of a 42 kDa "metal sensor" CzrA-DNA complex
EMSL Project ID
19835
Abstract
The ArsR (or ArsR/SmtB) family of winged helix-loop-helix proteins (ααααββα)regulate metal ion detoxification and resistance in prokaryotes under conditions of metal ion excess of both biologically required transition metal ions and heavy metal pollutants. The metalloregulatory Zn(II)/Co(II)-sensing sites of the transcriptional repressor, Staphylococcus aureus CzrA and the related sensor cyanobacterial SmtB, comprise a symmetry-related pair of subunit-bridging tetrahedral N3O α5 sites. Previous work has established that the metal-induced quaternary structural switch within the homodimer governs the DNA-binding affinity. We have initiated efforts to solve the solution structure of a 42 kD apo-CzrA:28-bp czrO (czr operator) complex. Complete HN, Cα, Cβ and stereospecific methyl group assignments for CzrA selectively protonated at Val-γ1,2, Leu-δ1,2 and Ile-δ1 methyl groups in an otherwise uniformly 2H, 15N, 13C-labeled background have been obtained for czrO-bound, apo and Zn2 states. However unambiguous assignments of intramolecular and intermolecular NOEs are significantly hindered by broad resonances and poor sensitivity in the NOE data acquired on our 600 MHz spectrometer Texas A&M. Here we propose a series of 3D and 4D NOE and other relaxation experiments acquired on high field spectrometers (800 and 900 MHz) for the structure determination of the Czra-DNA complex.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2006-08-08
End Date
2009-03-23
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Arunkumar AI, GC Campanello, and DP Glderoc. 2009. "Solution Structure of a Paradigm ArsR Family Zinc Sensor in the DNA-bound State." Proceedings of the National Academy of Sciences of the United States of America 106(43):18177-18182. doi:10.1073/pnas.0905558106
Arunkumar AI, MA Pennalla, X Kong, and DP Giedroc. 2007. "Resonance Assignments of the Metal Sensor CzrA in the apo-, Zn2- and DNA-bound (42 kDa) States." Biomolecular NMR Assignments 1:99-101. doi:10.1007/s12104-007-9027-y