Threading with explicit models for evolutionary conservation of structure and sequence

Proteins. 1999:Suppl 3:133-40. doi: 10.1002/(sici)1097-0134(1999)37:3+<133::aid-prot18>3.3.co;2-4.

Abstract

We have attempted to predict the three-dimensional structures of 19 proteins for the CASP3 experiment, each showing less than 25% sequence identity with known structures. Predictions were based on a threading method that aligns the target sequence with the conserved cores of structural templates, as identified from structure-structure alignments of the template with homologous neighbors. Alternative alignments were scored using contact potentials and a position-specific score matrix derived from sequence neighbors of the template. We find that this method identified the correct structural family for 11 of the 19 targets and predicted the remaining 8 targets to be similar to "none" of the templates, avoiding false positives. Threading alignments are relatively accurate for 10 of the 11 targets, including alignments for 6 of 7 identified at CASP3 as fold-recognition targets. These predictions were ranked "first place" by the CASP3 assessor when compared to fold-recognition predictions made by other methods. It appears that threading with family-specific models for structure and sequence conservation has improved threading prediction accuracy.

Publication types

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

MeSH terms

  • Algorithms
  • Carbamoyl-Phosphate Synthase (Ammonia) / chemistry
  • Carbon-Oxygen Lyases / chemistry
  • Conserved Sequence*
  • Escherichia coli / enzymology
  • Evolution, Molecular
  • Models, Molecular
  • Protein Folding
  • Proteins / chemistry*

Substances

  • Proteins
  • Carbon-Oxygen Lyases
  • methylglyoxal synthase
  • Carbamoyl-Phosphate Synthase (Ammonia)