@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 {1233,
	title = {Variable control of Ets-1 DNA binding by multiple phosphates in an unstructured region},
	journal = {Science},
	volume = {309},
	number = {5731},
	year = {2005},
	note = {ISI Document Delivery No.: 941KDTimes Cited: 66Cited Reference Count: 30},
	month = {Jul},
	pages = {142-145},
	type = {Article},
	abstract = {Cell signaling that culminates in posttranslational modifications directs protein activity. Here we report how multiple Ca2+-dependent phosphorylation sites within the transcription activator Ets-1 act additively to produce graded DNA binding affinity. Nuclear magnetic resonance spectroscopic analyses show that phosphorylation shifts Ets-1 from a dynamic conformation poised to bind DNA to a well-folded inhibited state. These phosphates lie in an unstructured flexible region that functions as the allosteric effector of autoinhibition. Variable phosphorylation thus serves as a "rheostat" for cell signaling to fine-tune transcription at the level of DNA binding.},
	keywords = {allosteric regulation, AUTOINHIBITION, DOMAIN, DYNAMICS, NMR-SPECTROSCOPY, PHOSPHORYLATION, PROTEIN, SITES, TRANSACTIVATION, TRANSCRIPTION FACTOR NFAT1},
	isbn = {0036-8075},
	url = {<Go to ISI>://000230212800079},
	author = {Pufall, M. A. and Lee, G. M. and Nelson, M. L. and Kang, H. S. and Velyvis, A. and Kay, L. E. and McIntosh, L. P. and Graves, B. J.}
}
@article {972,
	title = {Active site mutants of the "non-hydrolyzing" UDP-N-acetylglucosamine 2-epimerase from Escherichia coli},
	journal = {Biochimica Et Biophysica Acta-Proteins and Proteomics},
	volume = {1700},
	number = {1},
	year = {2004},
	note = {ISI Document Delivery No.: 833VCTimes Cited: 4Cited Reference Count: 26},
	month = {Jul},
	pages = {85-91},
	type = {Article},
	abstract = {The "non-hydrolyzing" bacterial UDP-N-acetylglucosamine 2-epimerase catalyzes the reversible interconversion of UDP-N-acetylglucosarnine (UDP-GlcNAc) and UDP-N-acetylmannosamine (UDP-ManNAc). This homodimeric enzyme is allosterically activated by its substrate, UDP-GlcNAc, and it is thought that one subunit plays a regulatory role, while that of the other plays a catalytic role. In this work, five active site mutants were prepared (D95N, E117Q, E131Q, K15A, and H213N) and analyzed in terms of their effects on binding, catalysis, and allosteric regulation. His213 appears to play a role in UDP binding and may also assist in catalysis and/or regulation, but is not a key catalytic residue. Lys15 appears to be quite important for binding. All three of the carboxylate mutants showed dramatic decreases in the value of k(cat) but relatively unaffected values of Km. Thus, these residues are playing key roles in catalysis and/or regulation. In the case of E117Q, the reaction intermediates are released into solution at a rate comparable to that of the overall catalysis. This may indicate that Glu117 plays the role as an acid/base catalyst in the second step of the UDP-GlcNAc epimerization reaction. All three carboxylate mutants were found to exhibit impaired allosteric control. (C) 2004 Elsevier B.V. All rights reserved.},
	keywords = {2-acetamidoglucal, 2-EPIMERASE/N-ACETYLMANNOSAMINE KINASE, ACID BIOSYNTHESIS, allosteric regulation, enterobacterial common antigen, EPIMERIZATION, HOMOLOGY, MECHANISM, MUTAGENESIS, RAT-LIVER, SEQUENCE, sialic acid, STREPTOCOCCUS-PNEUMONIAE, TRANSFERASES, UDP-N-acetylmannosamine},
	isbn = {1570-9639},
	url = {<Go to ISI>://000222367400011},
	author = {Samuel, J. and Tanner, M. E.}
}
