The Effect of Gamma-Ray-Induced Radicals on Activities and Membrane Structure of Sendai Virus in Aqueous Solutions

Abstract

The effects of gamma-ray-induced radicals on the activities of viruses and membrane proteins were studied with Sendai virus in aqueous suspensions with or without additives including OH scavengers. The activities measured were hemagglutination and hemolysis located in the viral membrane. The changes in the protein components of viruses were analyzed at the same time by polyacrylamide gel electrophoresis (PAGE). 2-Mercaptoethanol (70 mM) and p-aminobenzoic acid (1 mM), both known as OH scavengers, fully protected the viral activities from gamma-ray-induced inactivation. Deaeration of virus suspensions by bubbling argon through the suspension did not affect the inactivation curve of the activities of the virus. Conspicuous changes in the membrane-associated glycoprotein bands found by PAGE analysis generally coincided with the findings in the activities of the virus. These findings suggest that OH radicals are the major damaging species acting on the glycoproteins in the membrane, and result in the inactivation of viral functions. In spite of strong OH scavenging ability, t-butanol resulted in the enhancement of inactivation and a decrease in the intensity of glycoprotein bands in the PAGE pattern. This finding, which is seemingly contradictory to the above conclusion, is discussed in terms of the action of alcohol radicals generated after OH scavenging. In particular, the possibility is pointed out that the membrane structure is affected by the reaction with the alcohol radicals, causing a crucial alteration of embedded proteins.