Partial amino acid sequence of belladonna mottle virus coat protein

Abstract

The amino acid compn. of belladonna mottle virus coat protein indicated a high proline content like in other tymoviruses. The N-terminus of the protein was blocked by an acetyl group and CNBr cleavage yielded 19-, 15-, 14-, 5-, and 4-kilodalton (K) fragments. Of these, only 15 and 4K fragments were due to the cleavage at methionine residues, whereas the other fragments were products of acid hydrolysis. The 4K fragment was sequenced by manual dimethylaminoazobenzene isothiocyanate/phenyl isothiocyanate double coupling method. This sequence of 43 amino acids was similar to the C-terminal sequence of eggplant mosaic virus coat protein. The residues 142-160 of eggplant mosaic virus coat protein previously identified as a probable site of RNA-protein interactions showed 83% homol. with the N-terminal sequence of the 4K fragment of belladonna mottle virus coat protein.