Simian immunodeficiency virus from the sooty mangabey and rhesus macaque is modified with O-linked carbohydrate

J Virol. 2011 Jan;85(1):582-95. doi: 10.1128/JVI.01871-10. Epub 2010 Oct 20.


Although stretches of serine and threonine are sometimes sites for O-linked carbohydrate attachment, specific sequence and structural determinants for O-linked attachment remain ill defined. The gp120 envelope protein of SIVmac239 contains a serine-threonine-rich stretch of amino acids at positions 128 to 139. Here we show that lectin protein from jackfruit seed (jacalin), which binds to non- and monosialylated core 1 O-linked carbohydrate, potently inhibited the replication of SIVmac239. Selection of a jacalin-resistant SIVmac239 variant population resulted in virus with specific substitutions within amino acids 128 to 139. Cloned simian immunodeficiency virus (SIV) variants with substitutions in the 128-to-139 region had infectivities equivalent to, or within 1 log unit of, that of SIVmac239 and were resistant to the inhibitory effects of jacalin. Characterization of the SIVmac239 gp120 O-linked glycome showed the presence of core 1 and core 2 O-linked carbohydrate; a 128-to-139-substituted variant gp120 from jacalin-resistant SIV lacked O-linked carbohydrate. Unlike that of SIVmac239, the replication of HIV-1 strain NL4-3 was resistant to inhibition by jacalin. Purified gp120s from four SIVmac and SIVsm strains bound jacalin strongly in an enzyme-linked immunosorbent assay, while nine different HIV-1 gp120s, two SIVcpz gp120s, and 128-to-139-substituted SIVmac239 gp120 did not bind jacalin. The ability or inability to bind jacalin thus correlated with the presence of the serine-threonine-rich stretch in the SIVmac and SIVsm gp120s and the absence of such stretches in the SIVcpz and HIV-1 gp120s. Consistent with sequence predictions, two HIV-2 gp120s bound jacalin, while one did not. These data demonstrate the presence of non- and monosialylated core 1 O-linked carbohydrate on the gp120s of SIVmac and SIVsm and the lack of these modifications on HIV-1 and SIVcpz gp120s.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Amino Acid Substitution
  • Animals
  • Artocarpus / chemistry
  • Carbohydrates / chemistry*
  • Cercocebus atys / virology*
  • Drug Resistance, Viral
  • HIV Envelope Protein gp120 / chemistry*
  • HIV Envelope Protein gp120 / genetics
  • HIV Envelope Protein gp120 / metabolism
  • HIV-1 / drug effects
  • HIV-1 / genetics
  • HIV-1 / metabolism
  • Humans
  • Macaca mulatta / virology*
  • Molecular Sequence Data
  • Plant Lectins / chemistry
  • Plant Lectins / metabolism
  • Plant Lectins / pharmacology*
  • Simian Acquired Immunodeficiency Syndrome / virology
  • Simian Immunodeficiency Virus / chemistry*
  • Simian Immunodeficiency Virus / genetics
  • Simian Immunodeficiency Virus / metabolism


  • Carbohydrates
  • HIV Envelope Protein gp120
  • Plant Lectins
  • jacalin