NONLINEAR OPTICAL CIRCULAR DICHROISM FOR THE STUDY OF PROTEIN SECONDARY STRUCTURE AT SURFACES. Teresa P. Petralli-Mallow, A. L. Plant, J. C. Stephenson, L. J. Richter, and Janice M. Hicks, Building 221, Room B356, National Institute of Standards and Technology, Gaithersburg, MD 20899 (301-975-4625, email:


A nonlinear optical method, second harmonic generation-circular

dichroism (SHG-CD), can probe the chirality and orientation of

molecules at interfaces. By performing SHG-CD at wavelengths that are two-photon resonant with peptide backbone transitions, we aim to develop a method able to measure the secondary structure of proteins at surfaces. This nonlinear optical approach has potential for in situ measurements of the structure and orientation of proteins

at biological surfaces.