Terahertz spectroscopy of biomolecules in aqueous miscelles

PHYS 338

Catherine C. Cooksey, ccooksey@nist.gov and Edwin J. Heilweil, edwin.heilweil@nist.gov. Optical Technology Division, Physics Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899
Terahertz spectroscopy of biomolecules in aqueous environments is important for identifying global molecular structure and transient environmental interactions. However, water is an extremely strong absorber in the spectral range of 0.5 to 3 THz (15 cm-1 to 100 cm-1). To avoid bulk water absorption, we obtained the terahertz spectrum of the aqueous amino acid, Proline, in the frequency range of 35 cm-1 to 600 cm-1. This spectrum was acquired by solvating the amino acid within the interior water pool of aerosol-OT reverse micelles dispersed in transparent n-heptane. The effect of Proline concentration and reverse micelle size on the terahertz spectrum is reported, and the results are compared to the far-infrared spectra of Proline in bulk water and solid-phase. Results for small polypeptides, biomolecular dispersions, and solvent mixtures are also presented.
 

PHYS Poster Session - Optical Probes of Dynamics in Complex Environments
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A, Poster

Sci-Mix
8:00 PM-10:00 PM, Monday, April 7, 2008 Morial Convention Center -- Hall A, Sci-Mix

Division of Physical Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008