The envelope proteins of lactate dehydrogenase-elevating virus and their membrane topography.

Abstract

We have studied the membrane topography and N-glycosylation of the envelope proteins of lactate dehydrogenase-elevating virus (LDV, strain P). Transcripts of open reading frames (ORFs) 2, 5, and 6 were in vitro translated in the absence and presence of microsomal membranes, and the products analyzed for molecular weight, sensitivity to endoglycosidase F/N-glycosidase F and proteinases, and reaction with anti-LDV antibodies. The ORF 6 mRNA translation was enhanced in the presence of microsomal membranes. ORF 6 encodes a polytopic class III membrane protein identified as the nonglycosylated virion envelope protein (M/VP-2; approximately 18 kDa). The protein has a very short (about 11 amino acids) ectodomain, a longer (about 79 amino acids) C-terminal endodomain, and crosses the membrane three times between these domains. ORF 5 encodes the primary virion envelope glycoprotein (VP-3P) (25-42 kDa). Our results suggest that it is a polytopic class I glycoprotein. After removal of a signal peptide, the processed protein of about 171 amino acids consists of a short (approximately 30 amino acids) N-terminal ectodomain with three asparagine residues that appear to be N-glycosylated, a segment that crosses the membrane three times, and an about 74 amino acid long C-terminal endodomain. Neutralizing anti-LDV antibodies are probably directed to an epitope(s) in the N-terminal ectodomain. The ORF 2 protein is a standard class I glycoprotein with a single C-terminal membrane anchor segment and its signal peptide is removed during membrane-associated synthesis. The remaining ectodomain (about 165 amino acids) contains three asparagine residues which appear to be N-glycosylated. Our results suggest that the ORF 2 protein may be present in a low concentration in LDV virions (VP-3M).

• Authors: K S Faaberg, P G Plagemann
• Journal: Virology (Virology) Vol. 212 Issue 2 Pg. 512-25 (Oct 01 1995) ISSN: 0042-6822 [Print] United States
• PMID: 7571421 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Antibodies, Viral
• M-VP-2 protein, lactate dehydrogenase-elevating virus
• Membrane Glycoproteins
• VP-3 protein, lactate dehydrogenase-elevating virus
• Viral Envelope Proteins
• Viral Structural Proteins
• Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase
• Serine Endopeptidases

Topics

• Amino Acid Sequence
• Antibodies, Viral
• Base Sequence
• Cell Membrane (virology)
• Genes, Viral (genetics)
• Lactate dehydrogenase-elevating virus (chemistry, genetics, immunology)
• Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase
• Membrane Glycoproteins (chemistry, genetics)
• Microsomes (metabolism)
• Molecular Sequence Data
• Molecular Weight
• Open Reading Frames (genetics)
• Protein Biosynthesis
• Sequence Analysis, DNA
• Serine Endopeptidases
• Viral Envelope Proteins (chemistry, genetics, immunology)
• Viral Structural Proteins (genetics)
• Virion (chemistry)