On the Conformation of Phenylalanine Specific Transfer RNA Studies on Size and Shape of the Molecule by X‐Ray Small Angle Scattering

Abstract

The scattered X‐ray intensities from dilute solutions of tRNA phe (yeast) in 0.05 M Tris buffer at pH 7.5 were measured at 17°. The radius of gyration R (24.4Å), the molecular weight M (26100) and the volume V (41500 Å 3 ) were determined. A comparison of experimental with theoretical scattering curves of different bodies shows that the shape of the molecule cannot be well represented by a simple triaxial body. The calculated scattering curves which fit the measured scattering data best are for an elongated body with two different cross‐sections. No significant change of X‐ray small angle scattering was observed on increasing the temperature from 17° to 40°. At higher temperature the radius of gyration is increased with increasing temperature and at 70° the molecule has a random coil conformation.