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There is growing evidence that structural flexibility plays a central role in the function of protein molecules. Many of the experimental data come from nuclear magnetic resonance (NMR) spectroscopy, a technique that allows internal motions to be probed with exquisite time and spatial resolution. Recent methodological advancements in NMR have extended our(More)
Biological macromolecules are highly flexible and continually undergo conformational fluctuations on a broad spectrum of timescales. It has long been recognized that dynamics have an important role in the action of these molecules. However, the relationship between molecular function and motion is extremely challenging to delineate, because the(More)
Complexes between Src-homology 3 domains and proline-rich target peptides can have lifetimes on the order of milliseconds, making them too short-lived for kinetic characterization by conventional methods. Nuclear magnetic resonance (NMR) dynamics experiments are ideally suited to study such rapid binding equilibria, and additionally provide information on(More)
The ribonucleoprotein (RNP) domain is one of the most common eukaryotic protein domains, and is found in many proteins involved in recognition of a wide variety of RNAs. Two structures of RNA complexes of human U1A protein have revealed important aspects of RNP-RNA recognition, but have also raised intriguing questions concerning how RNP domains(More)
Allosteric transmission of information between distant sites in biological macromolecules often involves collective transitions between active and inactive conformations. Nuclear magnetic resonance (NMR) spectroscopy can yield detailed information on these dynamics. In particular, relaxation dispersion techniques provide structural, dynamic, and mechanistic(More)
Protein structure is inherently dynamic, with function often predicated on excursions from low to higher energy conformations. For example, X-ray studies of a cavity mutant of T4 lysozyme, L99A, show that the cavity is sterically inaccessible to ligand, yet the protein is able to bind substituted benzenes rapidly. We have used novel relaxation dispersion(More)
Low solubility is a major stumbling block in the detailed structural and functional characterization of many proteins and isolated protein domains. The production of some proteins in a soluble form may only be possible through alteration of their sequences by mutagenesis. The feasibility of this approach has been demonstrated in a number of cases where(More)
Recently developed carbon transverse relaxation dispersion experiments (Skrynnikov, N. R.; et al. J. Am. Chem. Soc. 2001, 123, 4556-4566) were applied to the study of millisecond to microsecond time scale motions in a cavity mutant of T4 lysozyme (L99A) using methyl groups as probes of dynamics. Protein expressed in E. coli cells with (13)CH(3)-pyruvate as(More)
Two new NMR experiments are presented for measuring side-chain dynamics in proteins. The first method, requiring 15N, 13C, approximately 50% 2H-labeled protein, measures 2H T1 and T1p spin relaxation times at side-chain positions. A second experiment permits the straightforward measurement of 13C-1H dipole-dipole cross-correlation relaxation rates at 13C(More)
Methyl axis (S2axis) and backbone NH (S2NH) order parameters derived from eight proteins have been analyzed. Similar distribution profiles for Ala S2axis and S2NH order parameters were observed. A good correlation between the two S2axis values of Val and Leu methyl groups is noted, although differences between order parameters can arise. The relation of(More)