The preparation and some properties of protein subunits obtained from wild cucumber mosaic virus

Abstract

Wild cucumber mosaic virus and two virus-like particles can be degraded markedly at high pH, e.g., pH 10 or at a low pH, e.g., pH 2.5. Virus protein subunits can be isolated from the degradation products by means of precipitation at pH 5.5. Ultracentrifuge analysis of the protein preparation thus obtained showed evidence of polydispersity under most of the solution conditions tested. These experiments indicated that the polydispersity was due to reactive groups which form hydrophobic interactions, hydrogen bonds, and disulfide bonds. The sedimentation rate of the principal component was approx. 2.0 S. Amino acid analysis was carried out on the protein from which the minimal molecular weight was calculated to be approx. 21500.