title: Characterization of the amino-terminal tryptic peptide of simian virus 40 small-t and large-T antigens.
abstract: Simian virus 40 small-t and large-T antigen were synthesized in vitro and labeled with methionine donated by initiator tRNA. Tryptic peptide fingerprinting was used to identify the amino-terminal peptide of the two proteins. Similar fingerprint analysis of small-t and large-T made in vitro in the absence of acetyl coenzyme A showed that the mobility of the amino-terminal peptide was changed under these conditions and suggested that it is acetylated. These data establish that the amino-terminal methionine residue of simian virus 40 small-t and large-T results from an initiation event, not post-translational cleavage, and provides additional evidence that the amino terminus of both proteins is acetylated. The identification of the amino-terminal peptide provides a useful marker for further studies on different forms of T-antigen from cells infected with and transformed by simian virus 40 and related viruses.
mesh_terms: D000107:Acetylation; D000951:Antigens, Neoplasm / Q000032:analysis*; D000956:Antigens, Viral / Q000032:analysis*; D010455:Peptides / Q000032:analysis; D013539:Simian virus 40 / Q000032:analysis / Q000276:immunology*; D014764:Viral Proteins / Q000032:analysis* / Q000096:biosynthesis
chemical_list: D000951:Antigens, Neoplasm; D000956:Antigens, Viral; D010455:Peptides; D014764:Viral Proteins