The SU and TM envelope protein subunits of bovine leukemia virus are linked by disulfide bonds, both in cells and in virions

Elizabeth R. Johnston, Kathryn Radke

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After the polyprotein precursor of retroviral envelope proteins is proteolytically cleaved, the surface (SU) and transmembrane (TM) subunits remain associated with each other by noncovalent interactions or by disulfide bonds. Disulfide linkages confer a relatively stable association between the SU and TM envelope protein subunits of Rous sarcoma virus and murine leukemia virus. In contrast, the noncovalent association between SU and TM of human immunodeficiency virus leads to significant shedding of SU from the surface of infected cells. The SU and TM proteins of bovine leukemia virus (BLV) initially were reported to be disulfide linked but later were concluded not to be, since TM is often lost during purification of SU protein. Here, we show that SU and TM of BLV do, indeed, associate through disulfide bonds, whether the envelope proteins are overexpressed in transfected cells, are produced in virus-infected cells, or are present in newly produced virions.

Original languageEnglish (US)
Pages (from-to)2930-2935
Number of pages6
JournalJournal of Virology
Issue number6
StatePublished - 2000


ASJC Scopus subject areas

  • Immunology

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