The interaction of the major structural polypeptides from the murine mammary tumor virus (MuMTV) and Rauscher murine leukemia virus (R-MuLV) with alkyl-agarose derivatives containing hydrocarbon arms of various lengths was examined. Both R-MuLV and MuMTV polypeptides were selectively adsorbed to octylimino (C8)-agarose and decylimino (C10)-agarose columns. Elution of proteins was accomplished using buffers containing 8.5 M ethylene glycol. In certain cases, polypeptides could only be removed from the columns by the addition of detergent to ethylene glycol-containing buffers. By examining the chromatographic behavior of polypeptides using (C8)- and (C10)-agarose columns and the conditions required for the elution of adsorbed proteins, we were able to determine the relative potential for hydrophobic interaction (degree of hydrophobicity) for each viral protein. The most hydrophobic polypeptide of MuMTV was found to be the glycoprotein gp34, while p15(E) and the gag precursor prp67 appeared to be the most hydrophobic of the R-MuLV proteins. The least hydrophobic polypeptides of MuMTV were p23 and p16, while those of R-MuLV were the two major internal proteins, p10 and p12. Four degrees of apparent hydrophobicity, from least hydrophobic to strongly hydrophobic, could be discerned by this procedure. The major core proteins (MuMTV p28, R-MuLV p30) of both viruses were slightly hydrophobic, while their major glycoproteins were moderately hydrophobic. The degree of hydrophobicity of oncornaviral polypeptides, as determined by hydrophobic chromatography, appeared to bear some relation to the different subviral components with which the proteins were associated. Our results indicate that hydrophobic chromatography may provide a new parameter for the characterization of oncornaviral polypeptides. This procedure should also prove applicable to the study of polypeptides from other viral systems.
ASJC Scopus subject areas