title: Conformational Dynamics and the Binding of Specific and Nonspecific DNA by the Autoinhibited Transcription Factor Ets-1.
abstract: The affinity of the Ets-1 transcription factor for DNA is autoinhibited by an intrinsically disordered serine-rich region (SRR) and a helical inhibitory module (IM) appended to its winged helix-turn-helix ETS domain. Using NMR spectroscopy, we investigated how Ets-1 recognizes specific versus nonspecific DNA, with a focus on the roles of protein dynamics and autoinhibition in these processes. Upon binding either DNA, the two marginally stable N-terminal helices of the IM predominantly unfold, but still sample partially ordered conformations. Also, on the basis of amide chemical shift perturbation mapping, Ets-1 associates with both specific and nonspecific DNA through the same canonical ETS domain interface. These interactions are structurally independent of the SRR, and thus autoinhibition does not impart DNA-binding specificity. However, relative to the pronounced NMR spectroscopic changes in Ets-1 resulting from specific DNA binding, the spectra of the nonspecific DNA complexes showed conformational exchange broadening and lacked several diagnostic amide and indole signals attributable to hydrogen bonding interactions seen in reported X-ray crystallographic structures of this transcription factor with its cognate DNA sequences. Such differences are highlighted by the chemical shift and relaxation properties of several interfacial lysine and arginine side chains. Collectively, these data support a general model in which Ets-1 interacts with nonspecific DNA via dynamic electrostatic interactions, whereas hydrogen bonding drives the formation of well-ordered complexes with specific DNA.
authors.affiliation: Department of Biochemistry and Molecular Biology, Department of Chemistry, and Michael Smith Laboratories, University of British Columbia , Vancouver, British Columbia V6T 1Z3, Canada.
authors.forename: Geneviève
authors.initials: G
authors.lastname: Desjardins
authors.affiliation: Department of Biochemistry and Molecular Biology, Department of Chemistry, and Michael Smith Laboratories, University of British Columbia , Vancouver, British Columbia V6T 1Z3, Canada.
authors.forename: Mark
authors.initials: M
authors.lastname: Okon
authors.affiliation: Department of Oncological Sciences, University of Utah School of Medicine, Huntsman Cancer Institute, University of Utah , Salt Lake City, Utah 84112-5550, United States.|Howard Hughes Medical Institute , Chevy Chase, Maryland 20815, United States.
authors.forename: Barbara J
authors.initials: BJ
authors.lastname: Graves
authors.affiliation: Department of Biochemistry and Molecular Biology, Department of Chemistry, and Michael Smith Laboratories, University of British Columbia , Vancouver, British Columbia V6T 1Z3, Canada.
authors.forename: Lawrence P
authors.initials: LP
authors.lastname: McIntosh
mesh_terms: D000818:Animals; D001120:Arginine / Q000737:chemistry; D001483:Base Sequence; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D008239:Lysine / Q000737:chemistry; D051379:Mice; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D050784:Proto-Oncogene Protein c-ets-1 / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D055672:Static Electricity
chemical_list: C494042:Ets1 protein, mouse; D050784:Proto-Oncogene Protein c-ets-1; D011994:Recombinant Proteins; D004247:DNA; D001120:Arginine; D008239:Lysine