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

@article{Johnston2000TheSA,
  title={The SU and TM envelope protein subunits of bovine leukemia virus are linked by disulfide bonds, both in cells and in virions.},
  author={Elizabeth R Johnston and Kathryn Radke},
  journal={Journal of virology},
  year={2000},
  volume={74 6},
  pages={2930-5}
}
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… CONTINUE READING