Characterization and localization of CIV polypeptides

Abstract

In order to detect the structural proteins linked with disulfide bonds, CIV was solubilized and electrophoresed under nonreducing conditions in the first dimension and then under reducing conditions in the second dimension. The viral polypeptides linked originally with disulfide bonds were separated into subunits. The complexes were trimers (P'50) or dimers (P60 and P10). The apparent molecular weights of P81, P53, and P49 changed significantly according to the composition of the lysis buffer used, suggesting that the differences in their molecular weights were due to conformational changes produced by reduction of their intramolecular disulfide bonds. Sulfhydryl-containing polypeptides (P'50-P50, P60, P100, and P33) were detected by N-[14C]ethylmaleimide, and the accessibility of these residues was analyzed after successive stripping of the CIV particle. Radioiodination of external polypeptides by [125I]iodosulfanilic acid shows only one intensively labeled spot corresponding to the P50 polypeptide, whereas P'50 was only slightly labeled. Six viral polypeptides P81, P60, P31, P17, P13, and P10 were revealed to possess high affinity for CIV DNA. A structural model of CIV is proposed and discussed.

Identification of the Gene Encoding the Major Capsid Protein of Insect Iridescent Virus Type 6 by Polymerase Chain Reaction

“…The major polypeptide represents about 40 % of the total viral proteins. Radioiodination of the external polypeptides revealed that P'50 is not directly exposed at the surface of the virus (Cerutti & Devauchelle, 1985. The detection of a high level of identity (more than 95 %) in the amino acid composition of the major capsid proteins of two members (TIV and IV22) of the family Iridoviridae led to the development of a strategy for detecting the major capsid protein of CIV using construction of specific oligonucleotide primers and PCR technology.…”

“…The major capsid protein of CIV consists of two polypeptides, a 150K protein composed of three identical disulphide-linked subunits of 50K (P'50) and a very similar 50K protein (P50) (Cerutti & Devauchelle, 1985). The major polypeptide represents about 40 % of the total viral proteins.…”

“…The CIV genome (209 kbp) is circularly permuted and terminally redundant (Delius et al, 1984;Schnitzler et al, 1987;Soltau et al, 1987;Fischer et al, 1990). CIV possesses a major capsid protein of about 50K (p50) as reported by Cerutti & Devauchelle (1985). The most important aspect which merits attention and support for research in this area is the biological relevance of iridoviruses.…”

Identification of the gene encoding the major capsid protein of fish lymphocystis disease virus

“…This conclusion is in agreement with the data reported in the present study. The MCP of CIV consists of two polypeptides, a 150K protein composed of three identical disulphide-linked subunits of 50K (P'50) and a very similar 50K protein (P50) (Cerutti & Devauchelle, 1985). Radioiodination of the external polypeptides revealed that P'50 is not directly exposed at the surface of the virus (Cerutti & Devauchelle, 1985 …”

The Structure of the T=147 Iridovirus, CIV, at 13Â Resolution

“…More than 30 polypeptides can be differentiated with 2D gel electrophoresis [2]. The major capsid protein (MCP), P50 (467 amino acids, 51.4 kDa), and that of PBCV-1, Vp54, share ~22% sequence identity [3][4][5]. The published 3D image reconstruction of CIV at 26Å resolution revealed that the protein shell (maximum diameter of 1850Å) consists of 12 pentavalent (pentamer) and 1460 hexavalent (trimer) capsomers, arranged with T=147 (h = 7, k = 7) icosahedral, quasi-equivalent symmetry [6].…”