Capsid polypeptides of mouse Elberfeld virus. I. Amino acid compositions and molar ratios in the virion
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Abstract:
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 hydrochloride. 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.
Insights
Researchers determined the composition and structure of mouse Elberfeld virus capsid proteins. All four major polypeptide chains were found in equal amounts within the virus particle.
Area of Science:
- Virology
- Structural Biology
- Biochemistry
Background:
- The capsid protein of the mouse Elberfeld (ME) virus is composed of four major polypeptide chains: alpha, beta, gamma, and delta.
- Understanding the precise composition and stoichiometry of these chains is crucial for elucidating the virus's structural integrity and assembly mechanisms.
Purpose of the Study:
- To isolate and determine the amino acid composition of the four major polypeptide chains of the ME virus capsid.
- To re-evaluate the molecular weights of the smallest chains of ME virus, mengovirus, and poliovirus.
- To determine the molar ratio of each polypeptide chain within the ME virion.
Main Methods:
- Preparative electrophoresis on polyacrylamide gels for polypeptide chain isolation and amino acid composition determination.
- Gel filtration chromatography in 6 M guanidine hydrochloride for molecular weight re-evaluation.
- Radiolabeling of ME virus with leucine or methionine, followed by quantitative analysis of radioactivity distribution in separated chains.
Main Results:
- The amino acid composition of each of the four major polypeptide chains (alpha, beta, gamma, delta) of the ME virus capsid was determined.
- The molecular weights of the smallest chains of ME virus, mengovirus, and poliovirus were re-determined to be approximately 7,300.
- Quantitative analysis revealed that all four polypeptide chains are present in equimolar proportions within the ME virion.
Conclusions:
- The ME virus capsid is composed of four distinct polypeptide chains present in equal molar ratios.
- The re-evaluated molecular weights and determined molar ratios provide a more accurate structural model for the ME virus capsid protein.