Amino-terminal sequence analysis of the structural proteins of Sindbis virus

The structural proteins of Sindbis virus, an enveloped virus which belongs to the Togavirus family, have been subjected to automated Edman degradation using improved techniques. Extensive NH2-terminal sequences of about 50 residues were determined for each of the two membrane glycoproteins. In both cases the NH2 terminus of the molecule was found to be similar in composition to typical water-soluble proteins. The viral capsid protein was found to have a blocked alpha-amino group. This is consistent with other observations that viral proteins derived from the NH2 terminus of precursor molecules are often blocked.