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Proceedings Paper

Difference Raman spectroscopic studies of ligand-protein interactions
Author(s): Hua Deng; Danny Manor; Gezhi Weng; Cun-Xiang Chen; Valeria Balogh-Nair; Robert H. Callender
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Paper Abstract

We summarize here our recent advancements in application of Raman spectroscopy to studies of protein-ligand interactions. Two main experimental strategies are shown to yield a wealth of information regarding the specific binding 'handles' which contribute to protein-ligand affinity and selectivity. Non-resonance Raman difference spectroscopy, in which the vibrational spectrum of the bound ligand is obtained by subtraction of the apo-protein spectrum from that of the complex is applied to chymotrypsin and aspartate aminotransferase. In both cases, vibrational information derived from previous resonance Raman measurements is shown to be misleading due to photochemically-induced changes in substrate conformation. Isotope editing extends the application of Raman difference spectroscopy to systems where measurements of the apo-protein spectrum is not a viable option because the bound ligand induces too many protein conformational changes that show up in the difference spectrum or in cases where the apoprotein is unstable. A difference spectrum is formed between the two protein-ligand complexes, one of which is specifically labeled with a stable isotope. Vibrational modes which are associated with the isotropic tag show as spectral shifts in the difference spectrum, while all other bands cancel. The power of this method is shown by studies the binding of phosphate of GDP to EF-Tu, the elongation factor from E. Coli. and of glucose-phosphate to phosphoglucomutase, PGM, where 18O labeling of phosphate reveals binding-induced changes in the vibrational modes of the phosphate moiety.

Paper Details

Date Published: 1 May 1993
PDF: 9 pages
Proc. SPIE 1890, Biomolecular Spectroscopy III, (1 May 1993); doi: 10.1117/12.145249
Show Author Affiliations
Hua Deng, City College/CUNY (United States)
Danny Manor, City College/CUNY (United States)
Gezhi Weng, City College/CUNY (United States)
Cun-Xiang Chen, City College/CUNY (United States)
Valeria Balogh-Nair, City College/CUNY (United States)
Robert H. Callender, City College/CUNY (United States)

Published in SPIE Proceedings Vol. 1890:
Biomolecular Spectroscopy III
Laurence A. Nafie; Henry H. Mantsch, Editor(s)

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