Solution structure of the capsid protein from the human T-cell leukemia virus type-I

J Mol Biol. 1999 Aug 13;291(2):491-505. doi: 10.1006/jmbi.1999.2986.


The solution structure of the capsid protein (CA) from the human T-cell leukemia virus type one (HTLV-I), a retrovirus that causes T-cell leukemia and HTLV-I-associated myelopathy in humans, has been determined by NMR methods. The protein consists of independent N and C-terminal domains connected by a flexible linker. The domains are structurally similar to the N-terminal "core" and C-terminal "dimerization" domains, respectively, of the human immunodeficiency virus type one (HIV-1) and equine infectious anemia virus (EIAV) capsid proteins, although several important differences exist. In particular, hydrophobic residues near the major homology region are partially buried in HTLV-I CA, which is monomeric in solution, whereas analogous residues in HIV-1 and EIAV CA project from the C-terminal domain and promote dimerization. These differences in the structure and oligomerization state of the proteins appear to be related to, and possibly controlled by, the oxidation state of conserved cysteine residues, which are reduced in HTLV-I CA but form a disulfide bond in the HIV-1 and EIAV CA crystal structures. The results are consistent with an oxidative capsid assembly mechanism, in which CA oligomerization or maturation is triggered by disulfide bo nd formation as the budding virus enters the oxidizing environment of the bloodstream.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Capsid / chemistry*
  • Capsid / genetics
  • Capsid / metabolism
  • Cysteine / metabolism
  • HIV-1 / chemistry
  • Horses
  • Human T-lymphotropic virus 1 / chemistry*
  • Humans
  • Infectious Anemia Virus, Equine / chemistry
  • Molecular Sequence Data
  • Nuclear Magnetic Resonance, Biomolecular
  • Oxidation-Reduction
  • Peptidylprolyl Isomerase / metabolism
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Sequence Homology, Amino Acid
  • Solutions


  • Recombinant Fusion Proteins
  • Solutions
  • Peptidylprolyl Isomerase
  • Cysteine

Associated data

  • PDB/1QRJ