FIG. 5.

Determination of molecular masses of affinity-purified His-VP3 polypeptides. (A) Mass spectrum of proteins recovered after affinity purification of extracts from FB/His-VP3-infected H5 cells. The sample was analyzed with a MALDI-TOF mass spectrometer. The molecular masses corresponding to the full-length and C-terminally trimmed VP3 products are indicated. (B) The diagram shows the sequence corresponding to the VP3 C-terminal end. The position of the VP3 proteolytic cleavage site (arrow) and the molecular mass of the 13-amino-acid peptide released by proteolytic cleavage are indicated.