Large-amplitude conformational changes in proteins, including loop motions, relative motions between domains, collective """"""""breathing"""""""" of protein cores, ligand-binding or oligomerization reactions, and overall folding-unfolding events, may be closely coupled, and in some instances rate-limiting, to biological functions such as molecular recognition, transitions along the catalytic cycle of enzymes, and inhibition or activation of proteins through intra-or inter-molecular protein-protein interactions. Mutations that perturb dynamical processes and conformational equilibria are associated with significant pathology, including loss or gain of function and misfolding. Recent developments, including those from the applicant laboratory, have opened new opportunities for investigation of large amplitude conformational dynamic processes on microsecond-millisecond time scales using NMR spin relaxation measurements at equilibrium in solution and with atomic site resolution, without potential complications introduced by non-native modifications necessary for other solution-state spectroscopic techniques. The proposed research has four primary objectives: (1) identification of the mechanistic basis for cell adhesion mediated by domain (strand) swapping in the cadherin superfamily, (2) assessment of the role of conformational mobility in catalysis by the essential enzyme ornithine 5'-monophosphate decarboxylase, (3) elucidation of the folding mechanism and description of the unfolded-state ensemble for the villin headpiece domain HP67, and (4) development of novel experimental and theoretical methods for characterizing protein dynamics on ?s-ms time scales. Time-dependent structural changes underlie the normal function of proteins, and misfunction in genetic diseases, cancer, and other pathologies;the proposed research will quantify this linkage for three protein systems involved in cellular structure and basic metabolism. Completion of these goals will enable additional future applications to a wide range of protein systems of biological importance.
The present proposal addresses the coupling between structure, dynamics, and function in cell adhesion mediated by cadherins, catalysis by the essential enzyme orotidine 5'-monophosphate decarboxylase, and folding of the villin headpiece domain. Elaboration of the roles of conformational dynamics in actuating and regulating these processes is essential for understanding the fundamental functions of proteins in human health and disease.
|Hsu, Andrew; O'Brien, Paul A; Bhattacharya, Shibani et al. (2018) Enhanced spectral density mapping through combined multiple-field deuterium 13CH2D methyl spin relaxation NMR spectroscopy. Methods 138-139:76-84|
|Koss, Hans; Rance, Mark; Palmer 3rd, Arthur G (2018) General Expressions for Carr-Purcell-Meiboom-Gill Relaxation Dispersion for N-Site Chemical Exchange. Biochemistry 57:4753-4763|
|Koss, Hans; Rance, Mark; Palmer 3rd, Arthur G (2017) General expressions for R1? relaxation for N-site chemical exchange and the special case of linear chains. J Magn Reson 274:36-45|
|Palmer 3rd, Arthur G (2016) A dynamic look backward and forward. J Magn Reson 266:73-80|
|Gill, Michelle L; Palmer 3rd, Arthur G (2015) Correction to ""Local isotropic diffusion approximation for coupled internal and overall molecular motions in NMR spin relaxation"". J Phys Chem B 119:3333|
|Palmer 3rd, Arthur G (2015) Enzyme dynamics from NMR spectroscopy. Acc Chem Res 48:457-65|
|Li, Ying; Rance, Mark; Palmer 3rd, Arthur G (2014) Rotation operator propagators for time-varying radiofrequency pulses in NMR spectroscopy: applications to shaped pulses and pulse trains. J Magn Reson 248:105-14|
|Gill, Michelle L; Palmer 3rd, Arthur G (2014) Local isotropic diffusion approximation for coupled internal and overall molecular motions in NMR spin relaxation. J Phys Chem B 118:11120-8|
|Sher, Inbal; Chang, Shih Chieh; Li, Ying et al. (2014) Conformational flexibility in the binding surface of the potassium channel blocker ShK. Chembiochem 15:2402-10|
|Palmer 3rd, Arthur G (2014) Chemical exchange in biomacromolecules: past, present, and future. J Magn Reson 241:3-17|
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