The E3 protein of bovine coronavirus is a receptor-destroying enzyme with acetylesterase activity.
In addition to members of the Orthomyxoviridae and Paramyxoviridae, several coronaviruses have been shown to possess receptor-destroying activities. Purified bovine coronavirus (BCV) preparations have an esterase activity which inactivates O-acetylsialic acid-containing receptors on erythrocytes. Diisopropyl fluorophosphate (DFP) completely inhibits this receptor-destroying activity of BCV, suggesting that the viral enzyme is a serine esterase. Treatment of purified BCV with [3H]DFP and subsequent sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the proteins revealed that the E3 protein was specifically phosphorylated. This finding suggests that the esterase/receptor-destroying activity of BCV is associated with the E3 protein. Furthermore, treatment of BCV with DFP dramatically reduced its infectivity in a plaque assay. It is assumed that the esterase activity of BCV is required in an early step of virus replication, possibly during virus entry or uncoating.
Vlasak
R
R
Department of Microbiology, Mount Sinai School of Medicine, New York, New York 10029-6574.
Luytjes
W
W
Leider
J
J
Spaan
W
W
Palese
P
P
D000115:Acetylesterase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D002417:Cattle; D002460:Cell Line; D003332:Coronaviridae / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D006023:Glycoproteins / Q000378:metabolism*; D006386:Hemagglutination Tests; D006387:Hemagglutination, Viral; D007531:Isoflurophate / Q000494:pharmacology; D011991:Receptors, Virus / Q000378:metabolism*; D010948:Viral Plaque Assay; D014764:Viral Proteins / Q000378:metabolism*; D014779:Virus Replication
D006023:Glycoproteins; D011991:Receptors, Virus; D014764:Viral Proteins; D007531:Isoflurophate; D000115:Acetylesterase