Solution structure of the B-Myb DNA-binding domain: a possible role for conformational instability of the protein in DNA binding and control of gene expression.McIntosh, P.B., Frenkiel, T.A., Wollborn, U., McCormick, J.E., Klempnauer, K.H., Feeney, J., Carr, M.D.
(1998) Biochemistry 37: 9619-9629
- PubMed: 9657674
- DOI: https://doi.org/10.1021/bi972861z
- Primary Citation of Related Structures:
- PubMed Abstract:
Double- and triple-resonance heteronuclear NMR spectroscopy have been used to determine the high-resolution solution structure of the minimal B-Myb DNA-binding domain (B-MybR2R3) and to characterize the specific complex formed with a synthetic DNA fragment corresponding to the Myb target site on the Myb-regulated gene tom-1. B-MybR2R3 is shown to consist of two independent protein domains (R2 and R3) joined by a short linker, which have strikingly different tertiary structures despite significant sequence similarities. In addition, the C-terminal region of B-Myb R2 is confirmed to have a poorly defined structure, reflecting the existence of multiple conformations in slow to intermediate exchange. This contrasts with the tertiary structure reported for c-MybR2R3, in which both R2 and R3 have the same fold and the C-terminal region of R2 forms a stable, well-defined helix [Ogata, K., et al. (1995) Nat. Struct. Biol. 2, 309-320]. The NMR data suggest there are extensive contacts between B-MybR2R3 and its DNA target site in the complex and are consistent with a significant conformational change in the protein on binding to DNA, with one possibility being the formation of a stable helix in the C-terminal region of R2. In addition, conformational heterogeneity identified in R2 of B-MybR2R3 bound to the tom-1-A target site may play an important role in the control of gene expression by Myb proteins.
Laboratory of Molecular Structure, National Institute for Biological Standards and Control, Potters Bar, UK.