N-glycosylation profiling of porcine reproductive and respiratory syndrome virus envelope glycoprotein 5.
Porcine reproductive and respiratory syndrome virus (PRRSV) is a positive-sense ssRNA virus whose envelope contains four glycoproteins and three nonglycosylated proteins. Glycans of major envelope glycoprotein 5 (GP5) are proposed as important for virus assembly and entry into permissive cells. Structural characterization of GP5 glycans would facilitate the mechanistic understanding of these processes. Thus, we purified the PRRSV type 2 prototype strain, VR2332, and analyzed the virion-associated glycans by both biochemical and mass spectrometric methods. Endoglycosidase digestion showed that GP5 was the primary protein substrate, and that the carbohydrate moieties were primarily complex-type N-glycans. Mass spectrometric analysis (HPLC-ESI-MS/MS) of GP5 N-glycans revealed an abundance of N-acetylglucosamine (GlcNAc) and N-acetyllactosamine (LacNAc) oligomers in addition to sialic acids. GlcNAc and LacNAc accessibility to ligands was confirmed by lectin co-precipitation. Our findings help to explain PRRSV infection of cells lacking sialoadhesin and provide a glycan database to facilitate molecular structural studies of PRRSV.
Department of Veterinary and Biomedical Sciences, University of Minnesota, 1971 Commonwealth Ave., St. Paul, MN 51108, USA.
Juan
J
Li
Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd., Athens, GA 30602, USA.
Shujuan
S
Tao
Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Rd., Athens, GA 30602, USA.
Ron
R
Orlando
Department of Veterinary and Biomedical Sciences, University of Minnesota, 1971 Commonwealth Ave., St. Paul, MN 51108, USA. Electronic address: murta001@umn.edu.
Michael P
MP
Murtaugh
D000117:Acetylglucosamine / Q000032:analysis*; D000606:Amino Sugars / Q000032:analysis*; D011232:Chemical Precipitation; D006026:Glycoside Hydrolases / Q000378:metabolism; D037102:Lectins / Q000378:metabolism; D013058:Mass Spectrometry; D019316:Porcine respiratory and reproductive syndrome virus / Q000737:chemistry*; D012794:Sialic Acids / Q000032:analysis*; D014759:Viral Envelope Proteins / Q000737:chemistry*
D000606:Amino Sugars; D037102:Lectins; D012794:Sialic Acids; D014759:Viral Envelope Proteins; C114789:glycoprotein 5, PRRSV; C000458:N-acetyllactosamine; D006026:Glycoside Hydrolases; D000117:Acetylglucosamine
GP5; GlcNAc; LacNAc; Lectin; Mass spectrometry; N-glycan; PRRSV; Veterinary virology; Virion structure