Photoradiobiological Research

The measurement of small angle neutron scattering in the solution of α-crystalline (concentration 8 mg/ml) with variation contrasts in four buffers has been carried out. The first buffer contained 100 % Н₂О, the second - 77 % Н₂О – 23 % D₂O, the third - 32 % Н₂О – 68 % D₂O, the fourth - 10 % Н₂О – 90 % D₂O. The preliminary analysis of observations was done. Radius of gyration and maximum size and volume of α-crystalline in buffers with different D₂O concentration were obtained. The values of these structural parameters are practically independent on D₂O concentration in buffer and are similar to the parameters obtained by the method of small angle X-ray scattering. The independence of gyration radius on D₂O concentration in buffer is evidence of homogeneous density of α-crystalline macromolecule. This is a new experimental fact.

The investigation of temperature realignment of α-crystalline macromolecule by the small angle neutron scattering method has been carried out as well. The measurements have been done with the buffer containing of 90 % D₂O at temperatures 20, 50, 60, 65, 75, 85 and 95 ^оС during the heating and cooling stages and with the buffer containing of 100 % Н₂О at 20 ^оС before and after heating to 95 ^оC. As a result of the experiments for the first time were obtained the structural data about α-crystalline by the small angle scattering method in wide range of high temperature (the measurements were carried out directly at high temperatures). These data will be used for analysis of α-crystalline realignment at high temperatures. This is important for understanding of mechanism of shaperon similar α-crystalline activity depending on temperature prehistory of this protein.