@article {2141,
	title = {The affinity of Ets-1 for DNA is modulated by phosphorylation through transient interactions of an unstructured region},
	journal = {Journal of Molecular Biology},
	volume = {382},
	number = {4},
	year = {2008},
	note = {ISI Document Delivery No.: 359YPTimes Cited: 3Cited Reference Count: 42Lee, Gregory M. Pufall, Miles A. Meeker, Charles A. Kang, Hyun-Seo Graves, Barbara J. McIntosh, Lawrence P.},
	month = {Oct},
	pages = {1014-1030},
	type = {Article},
	abstract = {Binding of the transcription factor Ets-1 to DNA is allosterically regulated by a serine-rich region (SRR) that modulates the dynamic character of the adjacent structured DNA-binding ETS domain and its flanking autoinhibitory elements. Multi-site phosphorylation of the flexible SRR in response to Ca2+ signaling mediates variable regulation of Ets-1 DNA-binding affinity. In this study, we further investigated the mechanism of this regulation. First, thermal and urea denaturation experiments demonstrated that phosphorylation of the predominantly unstructured SRR imparts enhanced thermodynamic stability on the well-folded ETS domain and its inhibitory module. We next identified a minimal fragment (residues 279-440) that exhibits both enhanced autoinhibition of Ets-1 DNA-binding and allosteric reinforcement by phosphorylation. To test for intramolecular interactions between the SRR and the rest of the fragment that were not detectable by H-1-H-1 NOE measurements, paramagnetic relaxation enhancements were performed using Cu2+ bound to the N-terminal ATCUN motif. Increased relaxation detected for specific amide and methyl groups revealed a preferential interaction surface for the flexible SRR extending from the inhibitory module to the DNA-binding interface. Phosphorylation enhanced the localization of the SRR to this surface. We therefore hypothesize that the positioning of the SRR at the DNA-binding interface and its role in shifting Ets-1 to an inhibited conformation are linked. In particular, transient interactions dampen the conformational flexibility of the ETS domain and inhibitory module required for high-affinity binding, as well as possibly occlude the DNA interaction site. Surprisingly, the phosphorylation-dependent effects were relatively insensitive to changes in ionic strength, suggesting that electrostatic forces are not the dominant mechanism for mediating these interactions. The results of this study highlight the role of flexibility and transient binding in the variable regulation of Ets-1 activity. (C) 2008 Elsevier Ltd. All rights reserved.},
	keywords = {allosteric regulation, ATCUN MOTIF, AUTOINHIBITION, BINDING, CHEMICAL-SHIFTS, DISORDERED PROTEIN, DOMAIN, DYNAMICS, GROUP HYDROGEN-EXCHANGE, NMR, paramagnetic relaxation, PARAMAGNETIC RELAXATION ENHANCEMENT, protein dynamics, SPECTROSCOPY, transcription},
	isbn = {0022-2836},
	url = {<Go to ISI>://000260024500017},
	author = {Lee, G. M. and Pufall, M. A. and Meeker, C. A. and Kang, H. S. and Graves, B. J. and McIntosh, L. P.}
}
@article {1165,
	title = {The structural and dynamic basis of Ets-1 DNA binding autoinhibition},
	journal = {Journal of Biological Chemistry},
	volume = {280},
	number = {8},
	year = {2005},
	note = {ISI Document Delivery No.: 902DTTimes Cited: 19Cited Reference Count: 73},
	month = {Feb},
	pages = {7088-7099},
	type = {Article},
	abstract = {The transcription factor Ets-1 is regulated by the allosteric coupling of DNA binding with the unfolding of an alpha-helix (HI-1) within an autoinhibitory module. To understand the structural and dynamic basis for this autoinhibition, we have used NAIR spectroscopy to characterize Ets-1DeltaN301, a partially inhibited fragment of Ets-1. The NMR-derived Ets-1DeltaN301 structure reveals that the autoinhibitory module is formed predominantly by the hydrophobic packing of helices from the N-terminal (HI-1, HI-2) and C-terminal (114, 115) inhibitory sequences, along with H1 of the intervening DNA binding ETS domain. The intramolecular interactions made by HI-1 in Ets-1DeltaN301 are similar to the intermolecular contacts observed in the crystal structure of an Ets-1DeltaN300 dimer, confirming that the latter represents a domain-swapped species. N-15 relaxation studies demonstrate that the backbone of the N-terminal inhibitory sequence is mobile on the nanosecond-picosecond and millisecond-microsecond time scales. Furthermore, hydrogen exchange measurements reveal that amide protons in helices HI-I and HI-2 exchange with water at rates only similar to15- and similar to75-fold slower, respectively, than predicted for an unfolded polypeptide. These findings indicate that inhibitory helices are only marginally stable even in the absence of DNA. The energetic coupling of DNA binding with the facile unfolding of the labile HI-1 provides a mechanism for modulating Ets-1 DNA binding activity via protein partnerships, post-translational modifications, or mutations. Ets-1 autoinhibition illustrates how conformational equilibria within structural domains can regulate macromolecular interactions.},
	keywords = {BACKBONE DYNAMICS, CHEMICAL-EXCHANGE, DIPOLAR COUPLINGS, Ets-1, GROUP HYDROGEN-EXCHANGE, HIGH-RESOLUTION, MURINE, N-15 NMR RELAXATION, POINTED DOMAIN, SECONDARY STRUCTURE, SIDE-CHAINS},
	isbn = {0021-9258},
	url = {<Go to ISI>://000227332700099},
	author = {Lee, G. M. and Donaldson, L. W. and Pufall, M. A. and Kang, H. S. and Pot, I. and Graves, B. J. and McIntosh, L. P.}
}
