PMID:11807232

Citation	Wurzer, WJ, Obojes, K and Vlasak, R (2002) The sialate-4-O-acetylesterases of coronaviruses related to mouse hepatitis virus: a proposal to reorganize group 2 Coronaviridae. J. Gen. Virol. 83:395-402
Abstract	Group 2 coronaviruses are characterized within the order Nidovirales by a unique genome organization. A characteristic feature of group 2 coronaviruses is the presence of a gene encoding the haemagglutinin-esterase (HE) protein, which is absent in coronaviruses of groups 1 and 3. At least three coronavirus strains within group 2 expressed a structural protein with sialate-4-O-acetylesterase activity, distinguishing them from other members of group 2, which encode an enzyme specific for 5-N-acetyl-9-O-acetylneuraminic acid. The esterases of mouse hepatitis virus (MHV) strains S and JHM and puffinosis virus (PV) specifically hydrolysed 5-N-acetyl-4-O-acetylneuraminic acid (Neu4,5Ac2) as well as the synthetic substrates p-nitrophenyl acetate, 4-methylumbelliferyl acetate and fluorescein diacetate. The K(m) values of the MHV-like esterases for the latter substrates were two- to tenfold lower than those of the sialate-9-O-acetylesterases of influenza C viruses. Another unspecific esterase substrate, alpha-naphthyl acetate, was used for the in situ detection of the dimeric HE proteins in SDS-polyacrylamide gels. MHV-S, MHV-JHM and PV bound to horse serum glycoproteins containing Neu4,5Ac2. De-O-acetylation of the glycoproteins by alkaline treatment or incubation with the viral esterases resulted in a complete loss of recognition, indicating a specific interaction of MHV-like coronaviruses with Neu4,5Ac2. Combined with evidence for distinct phylogenetic lineages of group 2 coronaviruses, subdivision into subgroups 2a (MHV-like viruses) and 2b (bovine coronavirus-like viruses) is suggested.
Links	PubMed
Keywords	Acetylesterase; Animals; Carboxylic Ester Hydrolases/metabolism; Cattle; Coronaviridae/classification; Coronaviridae/enzymology; Glycoproteins/metabolism; Hemagglutinins, Viral/metabolism; Humans; Mice; Murine hepatitis virus/classification; Murine hepatitis virus/enzymology; N-Acetylneuraminic Acid/metabolism; Rats; Substrate Specificity; Viral Fusion Proteins/metabolism
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
CVBQ:HEMA		GO:0001681: sialate O-acetylesterase activity	ECO:0000314:		F		Figure 2 demonstrates sialate O-acetylesterase activity	complete CACAO 4988
9GAMM:D7GNM7		GO:0016788: hydrolase activity, acting on ester bonds	ECO:0000314:		F		See Table 1	complete
SPIPL:Q53415		GO:0016788: hydrolase activity, acting on ester bonds	ECO:0000314:		F		Table 1.	complete

References

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