Long charge-rich alpha-helices in systemic autoantigens

Biochem Biophys Res Commun. 1993 Sep 15;195(2):686-96. doi: 10.1006/bbrc.1993.2100.


Autoimmune diseases are characterized by the presence of antibodies and T-cells targeting restricted sets of host proteins. This phenomenon may be due in part to greater non-specific immunogenicity for these proteins compared to others which are not autoantigenic. We used computer-based methods to analyze the sequenced human autoantigens for distinctive patterns of potential immunologic importance. Sequences longer than 27 residues predicted by these methods to form coiled-coil alpha-helices with a probability greater than 0.9 were detected in 40 of 109 (36.7%) of the known human autoantigens. These include many predominantly systemic disease-specific autoantigens not previously known to contain this structure. In comparison, 8.7% of human proteins in the Swissprot data base, and 1.1% of the proteins in the Brookhaven data base were found to contain such segments. These predicted coiled-coil alpha-helices are distinguished from most globular protein helices by greater length, higher charge content, and a heptad repeat multivalency. Coiled-coil segments correlate in part with known autoantibody epitopes and may contribute to autoantigenic potential. Systemic autoantigens generally are either basic or contain extended, multivalent, charge-rich segments such as coiled-coils.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Algorithms
  • Amino Acid Sequence
  • Autoantigens / chemistry*
  • Autoimmune Diseases / immunology*
  • Humans
  • Molecular Sequence Data
  • Organ Specificity
  • Probability
  • Protein Conformation
  • Protein Structure, Secondary*
  • Software


  • Autoantigens