The predicted primary structure of the peplomer protein E2 of the porcine coronavirus transmissible gastroenteritis virus.

The complete nucleotide sequence of cloned cDNAs containing the E2 glycoprotein-encoding region of the genome of transmissible gastroenteritis virus (TGEV) has been determined. A single large translatable frame of 4.3 kb starting at 8.2 kb from the 3' end of the genome was identified. Its deduced amino acid sequence contains the characteristic features of a coronavirus peplomer protein: the precursor polypeptide of TGEV E2 is 1447 residues long (i.e. 285 longer than the avian infectious bronchitis coronavirus spike protein); partial N-terminal sequencing demonstrated that a putative secretory signal sequence of 16 amino acids is absent in the virion-associated protein; the predicted mol. wt. of the apoprotein is 158K; most of the 32 potential N-glycosylation sites available in the sequence are presumed to be functional to account for the difference between this and the experimentally determined value (200K to 220K); a typical hydrophobic sequence near the C terminus is likely to be responsible for anchoring the peplomer to the virion envelope.