DETERMINANTS ESSENTIAL FOR THE TRANSMISSIBLE GASTROENTERITIS VIRUS-RECEPTOR INTERACTION RESIDE WITHIN A DOMAIN OF AMINOPEPTIDASE-N THAT IS DISTINCT FROM THE ENZYMATIC SITE
B. Delmas et al., DETERMINANTS ESSENTIAL FOR THE TRANSMISSIBLE GASTROENTERITIS VIRUS-RECEPTOR INTERACTION RESIDE WITHIN A DOMAIN OF AMINOPEPTIDASE-N THAT IS DISTINCT FROM THE ENZYMATIC SITE, Journal of virology, 68(8), 1994, pp. 5216-5224
The swine-specific coronavirus transmissible gastroenteritis virus (TG
EV) uses pig aminopeptidase-N (pAPN) as a cellular receptor. We showed
that the human aminopeptidase-N (hAPN) cannot substitute for pAPN in
this respect, although the two enzymes have 80% amino acid sequence id
entity. In order to map the TGEV binding site on pAPN, we constructed
a series of APN cDNA chimeras between pAPN and hAPN and analyzed them
for their capacity to confer infectivity. The region between residues
717 and 813 was found to be essential for infectivity. This region als
o contains the epitopes for three TGEV-blocking monoclonal antibodies
directed against pAPN. These data support the view that the catalytic
site and the TGEV receptor site are located in different domains. More
over, APN inhibitors and mutations in the catalytic site had no obviou
s effect on permissiveness for virus, thus providing evidence that the
APN enzymatic activity is not involved in the process of infection.