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Characterization of the sialic acid binding activity of transmissible gastroenteritis coronavirus by analysis of haemagglutination-deficient mutants

Authors :
Gert Zimmer
M. L. Ballesteros
Hans-Dieter Klenk
Luis Enjuanes
C. Krempl
G. Herrler
Source :
Europe PubMed Central
Publication Year :
2000
Publisher :
Microbiology Society, 2000.

Abstract

Transmissible gastroenteritis coronavirus (TGEV) agglutinates erythrocytes of several species by virtue of sialic acid binding activity of the surface protein S. We have isolated and characterized five haemagglutination-defective (HAD) mutants. In contrast to the parental virus, the mutants were unable to bind to porcine submandibulary mucin, a substrate rich in sialic acid. Each of the mutants was found to contain a single point mutation in the S protein (Cys155Phe, Met195Val, Arg196Ser, Asp208Asn or Leu209Pro), indicating that these amino acids are affecting the sialic acid binding site. In four of the HAD mutants a nearby antigenic site is affected in addition to the sialic acid binding site, as indicated by reactivity with monoclonal antibodies. The parental virus was found to have an increased resistance to the detergent octylglucoside compared to the HAD mutants. This effect depended on cellular sialoglycoconjugates bound to the virion. If the binding of sialylated macromolecules was prevented by neuraminidase treatment, the parental virus was as sensitive to octylglucoside as were the HAD mutants. We discuss the possibility that the sialic acid binding activity helps TGEV to resist detergent-like substances encountered during the gastrointestinal passage and thus facilitates the infection of the intestinal epithelium. An alternative function of the sialic acid binding activity – accessory binding to intestinal tissues – is also discussed.

Details

ISSN :
14652080 and 13500872
Volume :
81
Database :
OpenAIRE
Journal :
Microbiology
Accession number :
edsair.doi.dedup.....3b2f0d0f17cf3d731b09b354c767c9dc
Full Text :
https://doi.org/10.1099/0022-1317-81-2-489