Multiple chemical forms of hepatitis B surface antigen produced in yeast.
Hepatitis B surface antigen (HBsAg) has been extracted from yeast cells that produce HBsAg. These cells contain the gene for surface antigen carried on a plasmid that replicates in the cells. Analysis of the yeast-derived HBsAg by sucrose gradient centrifugation and by polyacrylamide gel electrophoresis shows that the antigen that is initially released from yeast cells is a high molecular weight aggregate of the fundamental Mr 25,000 subunit. Unlike HBsAg derived from human plasma, the yeast antigen is held together by noncovalent interactions and can be dissociated in 2% NaDodSO4 without the use of reducing agents. During in vitro purification of the yeast antigen, some disulfide bonds form spontaneously between the antigen subunits, resulting in a particle composed of a mixture of monomers and disulfide-bonded dimers. Treatment with 3 M thiocyanate converts the 20-nm particles into a fully disulfide-bonded form that is not disrupted in NaDodSO4 unless a reducing agent is added. This disulfide-bonded particle resembles the naturally occurring, plasma-derived surface antigen particle, and the in vitro formed particle has been used to prepare a vaccine for humans against hepatitis B virus infection.
Wampler
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Lehman
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Boger
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McAleer
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WJ
Scolnick
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D000426:Alcohol Dehydrogenase; D000429:Alcohol Oxidoreductases / Q000235:genetics; D005796:Genes; D005800:Genes, Fungal; D005814:Genes, Viral; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics; D006514:Hepatitis B Surface Antigens / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D010957:Plasmids; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics*
D006514:Hepatitis B Surface Antigens; D011994:Recombinant Proteins; D000429:Alcohol Oxidoreductases; D000426:Alcohol Dehydrogenase; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases