1BYM

SOLUTION STRUCTURES OF THE C-TERMINAL DOMAIN OF DIPHTHERIA TOXIN REPRESSOR

Summary for 1BYM

• Entry DOI: 10.2210/pdb1bym/pdb
• Descriptor: PROTEIN (DIPHTHERIA TOXIN REPRESSOR) (1 entity in total)
• Functional Keywords: repressor, dtxr, c-terminal domain, prokaryotic sh3 domain, transcription regulation, peptide-binding, gene regulation
• Biological source: Corynebacterium diphtheriae
• Total number of polymer chains: 1
• Total formula weight: 10609.80

Authors

Wang, G.,Wylie, G.P.,Twigg, P.D.,Caspar, D.L.D.,Murphy, J.R.,Logan, T.M. (deposition date: 1998-10-17, release date: 1998-10-21, Last modification date: 2024-05-22)

Primary citation

Wang, G.,Wylie, G.P.,Twigg, P.D.,Caspar, D.L.,Murphy, J.R.,Logan, T.M.
Solution structure and peptide binding studies of the C-terminal src homology 3-like domain of the diphtheria toxin repressor protein.
Proc.Natl.Acad.Sci.USA, 96:6119-6124, 1999

PubMed Abstract: The diphtheria toxin repressor (DtxR) is the best-characterized member of a family of homologous proteins that regulate iron uptake and virulence gene expression in the Gram-positive bacteria. DtxR contains two domains that are separated by a short, unstructured linker. The N-terminal domain is structurally well-defined and is responsible for Fe2+ binding, dimerization, and DNA binding. The C-terminal domain adopts a fold similar to eukaryotic Src homology 3 domains, but the functional role of the C-terminal domain in repressor activity is unknown. The solution structure of the C-terminal domain, consisting of residues N130-L226 plus a 13-residue N-terminal extension, has been determined by using NMR spectroscopy. Residues before A147 are highly mobile and adopt a random coil conformation, but residues A147-L226 form a single structured domain consisting of five beta-strands and three helices arranged into a partially orthogonal, two-sheet beta-barrel, similar to the structure observed in the crystalline Co2+ complex of full-length DtxR. Chemical shift perturbation studies demonstrate that a proline-rich peptide corresponding to residues R125-G139 of intact DtxR binds to the C-terminal domain in a pocket formed by residues in beta-strands 2, 3, and 5, and helix 3. Binding of the proline-rich peptide by the C-terminal domain of DtxR presents an example of peptide binding by a prokaryotic Src homology 3-like protein. The results of this study, combined with previous x-ray studies of intact DtxR, provide insights into a possible biological function of the C-terminal domain in regulating repressor activity.

PubMed: 10339551
DOI: 10.1073/pnas.96.11.6119

Experimental method

SOLUTION NMR