Synthesis and Processing of the Bovine Enteric Coronavirus Haemagglutinin Protein

Abstract

SUMMARYThe haemagglutinin molecule on the bovine enteric coronavirus has been identified as a glycoprotein of 140K composed of disulphide-linked subunits of 65K. In this study, we have shown the subunits to be identical by demonstrating an unambiguous aminoterminal amino acid sequence. The unglycosylated subunit was found to have an M r of 42.5K and to undergo rapid disulphide linkage and glycosylation. Glycosylation was found to be of the asparagine-linked type and some of the oligosaccharides underwent processing to complex forms. Studies with inhibitors of glycosylation suggested that a processing of the haemagglutinin oligosaccharide takes place on the virion whilst it is in the Golgi apparatus. Each haemagglutinin subunit on the mature virion was estimated to possess six or seven carbohydrate chains of either the high-mannose or hybrid type, and three or four chains of the complex type.

Molecular Interactions in the Assembly of Coronaviruses

“…The HE gene encodes a type I membrane protein of 424-439 residues that contains a cleavable signal peptide at its amino terminus (Hogue et al, 1989;Kienzle et al, 1990) and a transmembrane domain close to its carboxy terminus, leaving a short cytoplasmic tail of about 10 residues (Fig. 4).…”

“…However, influenza C virus, toroviruses, and coronaviruses may well have acquired their HE sequences independently, not from each other but from yet another source (Cornelissen et al, 1997). The HE protein becomes cotranslationally N-glycosylated when expressed in cells, giving rise to a polypeptide of approximately 60-65 kDa that rapidly forms disulfide-linked dimers (Hogue et al, 1989;Kienzle et al, 1990;King et al, 1985;Parker et al, 1989;Yokomori et al, 1989;Yoo et al, 1992). The HE dimers (or a higher order structure thereof) become incorporated into virions, while a proportion is transported to the cell surface (Kienzle et al, 1990;Pfleiderer et al, 1991).…”

Three-dimensional visualization of the rotavirus hemagglutinin structure

“…Several more examples of multimeric hemagglutinins can be found in other virus families. The hemagglutinin of coronavirus, also an enteric virus, functions as a dimer (Hogue et al, 1989). The wellstudied influenza hemagglutinin is a trimer (Wiley and Skehel, 1987).…”

A review of feline infectious peritonitis virus: molecular biology, immunopathogenesis, clinical aspects, and vaccination

“…It is a glycoprotein of approximately 65kDa which functionally exists as a dimer (Hogue, et al, 1989;Spaan, et al, 1988 ). This protein from BCV has been shown to have hemagglutinating activity and to be a "receptor-destroying enzyme with acetylesterase activity" (Hogue, et al, 1989;Spaan, et al, 1988;Storz, et al, 1991;Vlasak, et al, 1988). Recent work, however, indicates that the S protein of BCV is actually a more efficient hemagglutinin than the HE protein (Schultze, et al, 1991 ).…”