Zur N-terminalen Konfiguration der Peptiduntereinheit im Protein des Tabakmosaikvirus

Abstract

By degradation of the tobacco mosaic virus (TMV) protein with chymotrypsin and pepsin, the peptides Ala-Asp-Pro-Heu-Glu-Leu and Asp-Pro-Leu-Val-Thr were isolated. They contained the sequences Pro-Ileu-Glu and Pro-Leu-Val, previously assumed to be N-terminal groups. Further, the structure of the acetyl-seryltyrosine dipeptide found by Narita was confirmed. In the isolated peptides and in synthetic [alpha]-aspartyl-proline peptides the linkage between asp and pro is very labile to acidic hydrolysis. This explains why the proline sequences were found as terminal groups in the TMV protein after treatment with trichloroacetic acid. The [epsilon] -amino groups of both lysine residues in the peptide chain react with fluorodinitro-benzine. Therefore a side-chain cannot be attached to these amino groups. The results support a linear structure of the peptide chain with N-terminal acetyl-seryl-tyrosine as suggested by Narita and Frankel-Conrat.