Abstract
April 11, 2007
4:30 pm, 700 Clark Hall
Cornell University Biophysics Colloquium

High and Low Resolution Solid-State NMR Spectroscopy of Proteins: Studies of Structure and Enzymatic Reactivity


Tatyana Polenova
Assistant Professor
Department of Chemistry and Biochemistry
Website

Host: Linda Nicholson, 255-7208

General approaches for resonance assignments and structural analysis in uniformly and differentially enriched proteins and protein assemblies by magic angle spinning NMR spectroscopy are discussed using a 108-amino acid residue E.coli thioredoxin as an example. It will be demonstrated that a combination of multidimensional homo- and hetero-nuclear correlation experiments yield nearly complete resonance assignments for the uniformly enriched full-length protein as well as for two differentially enriched non-covalent complexes formed by its complementary fragments. Secondary and tertiary structure analysis is presented. The practical considerations for high-resolution solid-state NMR studies of uniformly enriched polypeptides are outlined, including sample preparation protocol, instrumentation and pulse sequences. The potential of employing differential labeling strategies for high-resolution structural studies of protein interfaces and protein assemblies by solid-state NMR spectroscopy is addressed.

In the second part of the lecture, 51V solid-state MAS NMR spectroscopy will be introduced as a direct probe of the geometric and electronic environments of vanadium sites in proteins. Experimental results will be presented for a 67.5 kDa vanadium chloro- and bromo-peroxidases. Potential for combined experimental-NMR and theoretical-DFT analysis of vanadium sites in inorganic systems and proteins is analyzed.

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