[Properties of informosomes fixed by ultraviolet irradiation]

The conditions for UV irradiation (lambda = 254 nm) of ribonucleoprotein preparations containing informosomes were elaborated which provide for complete fixation of informosomal proteins on RNA. The degree of fixation was controlled by centrifugation in a CsCl density gradient. It was found that complete fixation of informosomes from loach embryos was achieved by irradiation with greater than or equal to 250 quanta per nucleotide. Fixation of informosomes isolated from Krebs ascite carcinoma II was observed during irradiation with higher (720 quanta per nucleotide) doses. It was shown that the irradiation doses used do not cause the destruction of ribonucleoprotein particles of RNA degradation. No fixation of ribosomal particles was observed during irradiation with the above doses. The method described can be used for the isolation of informosomes with the use of density gradients for the analysis of polypeptide composition of these particles.