Time-dependent correlation functions of histone lysine-rich (HL) in tris buffer (0.01 M tris, 0.14 M NaCl at pH=8) were measured by means of a 96-channel single-clipped digital photon correlation spectrometer over a range of scattering angles at 25?C and three different concentrations (3.4, 4.5, and 7.1 mg/ml). Several models as well as the method of cumulants were used to analyze our experimental data which were found to contain at least two decay times. By approximating the heterogeneous lysine-rich histone and its aggregates as spheres of two distinct sizes, we obtained a molecular weight of 1.1?10 4 for our unaggregated (HL) histone and a corresponding diffusion coefficient D? of 8.5?10 -7 cm 2/sec at 25?C and infinite dilution. Our diffusion-coefficient results differ from a previous linewidth study of arginine-rich histone by a factor of 10. It implies that in quasielastic laser scattering large aggregates, even though small in number, can play an extremely important role in data analysis and must be taken into account properly. Copyright ? 1976 American Institute of Physics.
Relation:
The Journal of Chemical Physics Volume 65, Issue 11, 1976, Pages 4508-4511
