A polarized and depolarized dynamic light scattering study of the tRNAphe conformation in solution

✍ Scribed by A. Patkowski; W. Eimer; Th. Dorfmüller

• Publisher: Wiley (John Wiley & Sons)
• Year: 1990
• Tongue: English
• Weight: 997 KB
• Volume: 30
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.360300111

✦ Synopsis

The dynamics of tRNAPhe from brewer's yeast in solution was studied over a broad concentration and temperature range by polarized and depolarized dynamic light scattering. It is shown that measurements of the depolarized Rayleigh spectrum with a high-resolution confocal Fabry-Perot interferometer provide very accurate values for the rotational diffusion coefficient of the biopolymer. The translational diffusion coefficient was determined by polarized photon correlation spectroscopy. A combination of both transport coefficients allows one to calculate the hydrodynamic size of tRNAPhe using the Perrin equations for an biaxial ellipsoid. Within a temperature range from 9 to 45"C, the tRNAPhe molecule adopts a nearly spherical shape. The dimensions are similar to the previously proposed U-shaped structure. In the melting region a second relaxation process was observed that is attributed to the collective reorientation of the bases. The concentration dependence of' the rotational diffusion coefficient of tRNAPhe in the concentration range of 2-75 mg/mL exhibits a slightly positive slope, in agreement with previous experimental findings and in contradiction to the theoretical predictions based on hydrodynamic interactions in solution,