The four major polypeptide chains (alpha, beta, gamma, delta) constituting the capsid protein of mouse Elberfeld (ME) virus were isolated by preparative electrophoresis on polyacrylamide gels, and the amino acid composition of each chain was determined. In addition, the molecular weights of the smallest chains of ME virus, mengovirus, and poliovirus, which had previously been determined by gel electrophoretic methods, were redetermined by gel filtration chromatography in 6 M guanidine

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... ide. Each was found to have a molecular weight about 7,300. Using the reevaluated molecular weights and the known amino acid compositions of the chains, the molar ratio of each chain in the ME virion was determined by quantitative analysis of the distribution of radioactivity in the electrophoretically separated chains of virus which had been specifically radiolabeled with leucine or with methionine. Equimolar proportions of all four chains were found in the virion. 0.1% SDS, 0.1% (v/v) N, N, N',N'-tetramethylethylenediamine, and 0.05% ammonium persulfate. Electrophoresis was for 5 hr at 8 ma per tube using 0.1% SDS in 0.1 M sodium phosphate, pH 7.2, as electrode buffer. The alpha, beta, and gamma chains, which 347 on May 8, 2020 by guest