Haemagglutinin-esterase protein (HE) of murine corona virus: DVIM (diarrhea virus of infant mice).
The acetylesterase (AE) activity of DVIM (diarrhea virus of infant mice) was assigned to the haemagglutinin-esterase (HE) protein. The substrate specificity was examined using the natural substrate bovine submaxillary mucin (BSM) and/or synthetic substrates p-nitrophenylacetate (p-NiA) and alpha-naphthylacetate (alpha-NA) and compared with several strains of MHV and influenza viruses. The AE of DVIM hydrolyzed the O-acetylester bond of BSM, and the two synthetic substrates p-NiA and alpha-NA in vitro. MHV-S reacted efficiently with both p-NiA and alpha-NA but less with BSM. Influenza virus (C/Miyagi/77) reacted with BSM efficiently, however reacted with p-NiA weakly, but not with alpha-NA at all. Thus, the AE-reactivity of DVIM was distinctly different from that of MHV-S and influenza C virus, suggesting that the AE of HE may have a modified function. Isolation of HE by the treatment with non ionic detergent NP40, resulted in globules approximately 5 nm in diameter. DVIM-binding proteins were demonstrated in the plasma membrane of mouse intestinal brush-border cells and hepatocytes. The same protein was recognized by MHV-S and MHV-4. The cell membranes obtained from these target tissues were substrates for the AE of DVIM. The biological importance of the HE protein for DVIM is discussed.
Sugiyama
K
K
Department of Biology, Faculty of Science, Hirosaki University, Japan.
Kasai
M
M
Kato
S
S
Kasai
H
H
Hatakeyama
K
K
D000115:Acetylesterase / Q000032:analysis* / Q000302:isolation & purification; D000818:Animals; D017934:Coronavirus / Q000201:enzymology*; D005260:Female; D006389:Hemagglutinins, Viral / Q000032:analysis* / Q000302:isolation & purification / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D013379:Substrate Specificity; D014760:Viral Fusion Proteins; D014764:Viral Proteins / Q000032:analysis* / Q000302:isolation & purification / Q000502:physiology
D006389:Hemagglutinins, Viral; D014760:Viral Fusion Proteins; D014764:Viral Proteins; C060814:hemagglutinin esterase; D000115:Acetylesterase