Fig. 1.

Schematic drawing of the truncated pAPN constructs and functional activities. Five recombinant plasmids bearing either the signal peptide sequence-deleted pAPN (pAPN) or four truncated pAPN (T/pAPNs) were constructed using conventional molecular cloning techniques. The name and insert length of the constructs are indicated. Their ability in binding to either an anti-pAPN antibody or TGE virions are indicated inferred from the results of Western blot, plaque asssays or ELISA. “+” means positive reaction or effect; “−” means negative result. The infection inhibition rate shows the maximum inhibition ability of the pAPN proteins to cell infection by TGEV. It should be noted that the sizes of the lines are not proportional to the length of the amino acid chain. The details on the inhibition ability of the pAPN proteins to TGEV infection or binding to the antibody or virions are shown in other figures.