@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 {4365,
	title = {Conformation of native, reduced and [5-55](Ala) bovine pancreatic trypsin inhibitor in the gas phase},
	journal = {Rapid Communications in Mass Spectrometry},
	volume = {12},
	number = {1},
	year = {1998},
	note = {ISI Document Delivery No.: YQ873Times Cited: 14Cited Reference Count: 46},
	pages = {40-44},
	type = {Article},
	abstract = {Collision cross sections have been measured for gas phase ions of native oxidized bovine pancreatic trypsin inhibitor (BPTI), native reduced BPTI and a mutant form of BPTI containing a single disulphide bond between residues 5 and 55 ([5-55](Ala) BPTI). Cross sections for [5-55](Ala) BPTI and reduced BPTI were 9\% and 17\% greater respectively than those for native BPTI, Cross sections for native BPTI were smaller than previous estimates from the crystal structure but in reasonable agreement with values calculated from the radius of gyration determined by x-ray scattering from solution BPTI. The increase in cross section for reduced BPTI over native BPTI is similar to that seen in molecular dynamics simulations, The results show that the disulphide bonds of BPTI contribute to the folding of the gas phase ions, but that even in the absence of disulphide bonds the protein ions maintain compact structures. Comparisons to relative areas calculated from hydrodynamic radii of BPTI in solution suggest that when disulphide linkages are removed, BPTI in the gas phase unfolds less than BPTI in solution. (C) 1998 John Wiley \& Sons, Ltd.},
	keywords = {BPTI, DISULFIDE BOND, IONS, MASS-SPECTROMETRY, MOLECULAR-DYNAMICS SIMULATIONS, MYOGLOBIN, protein dynamics, STABILITY},
	isbn = {0951-4198},
	url = {<Go to ISI>://000071433000008},
	author = {Nesatiy, V. and Chen, Y. L. and Collings, B. A. and Douglas, D. J.}
}
