VIBRATIONAL CIRCULAR DICHROISM SPECTRA OF FOUR DISTINCT CONFORMATIONAL STATES OF POLY(L-LYSINE) IN AQUEOUS SOLUTION
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Date
1986
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Ohio State University
Abstract
Fourier transform infrared vibrational circular dichroism spectra in the amide I' region of poly(L-lysine) in $D_{2}O$ solutions have confirmed the existence of three distinct conformational states and an unordered state in this homo-polypeptide, each with a unique, characteristic VCD spectrum. The right-handed $\alpha$-helix gives rise to a (-+-) VCD pattern, the antiparallel $\beta$-sheet to two strong negative features, and the extended helix (formerly denoted the random coil) to a (+-) VCD couplet, for the amide I' vibrations. In addition, a completely unordered conformation can be obtained which is characterized by the absence of any amide I' VCD. The negative VCD in the $\beta$-sheet conformation is interpreted in terms of vibrationally generated ring currents.
Description
Examples of amide I' VCD spectra for several proteins with known conformational composition shows that these characteristic VCD patterns can also be observed in complex systems. Address: Department of Chemistry, Syracuse University, Syracuse, NY 13244-1200
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