Ab initio prediction of peptide-MHC binding geometry for diverse class I MHC allotypes

Andrew J. Bordner, Ruben Abagyan

Research output: Contribution to journalArticle

63 Scopus citations

Abstract

Since determining the crystallographic structure of all peptide-MHC complexes is infeasible, an accurate prediction of the conformation is a critical computational problem. These models can be useful for determining binding energetics, predicting the structures of specific ternary complexes with T-cell receptors, and designing new molecules interacting with these complexes. The main difficulties are (1) adequate sampling of the large number of conformational degrees of freedom for the flexible peptide, (2) predicting subtle changes in the MHC interface geometry upon binding, and (3) building models for numerous MHC allotypes without known structures. Whereas previous studies have approached the sampling problem by dividing the conformational variables into different sets and predicting them separately, we have refined the Biased-Probability Monte Carlo docking protocol in internal coordinates to optimize a physical energy function for all peptide variables simultaneously. We also imitated the induced fit by docking into a more permissive smooth grid representation of the MHC followed by refinement and reranking using an all-atom MHC model. Our method was tested by a comparison of the results of cross-docking 14 peptides into HLA-A*0201 and 9 peptides into H-2K b as well as docking peptides into homology models for five different HLA allotypes with a comprehensive set of experimental structures. The surprisingly accurate prediction (0.75 Å backbone RMSD) for cross-docking of a highly flexible decapeptide, dissimilar to the original bound peptide, as well as docking predictions using homology models for two allotypes with low average backbone RMSDs of less than 1.0 Å illustrate the method's effectiveness. Finally, energy terms calculated using the predicted structures were combined with supervised learning on a large data set to classify peptides as either HLA-A*0201 binders or nonbinders. In contrast with sequence-based prediction methods, this model was also able to predict the binding affinity for peptides to a different MHC allotype (H-2Kb), not used for training, with comparable prediction accuracy.

Original languageEnglish (US)
Pages (from-to)512-526
Number of pages15
JournalProteins: Structure, Function and Genetics
Volume63
Issue number3
DOIs
StatePublished - May 15 2006

Keywords

  • Homology models
  • Major histocompatibility complex (MHC)
  • Monte Carlo optimization
  • Peptide binding prediction
  • Peptide docking
  • Potential grid

ASJC Scopus subject areas

  • Structural Biology
  • Biochemistry
  • Molecular Biology

Fingerprint Dive into the research topics of 'Ab initio prediction of peptide-MHC binding geometry for diverse class I MHC allotypes'. Together they form a unique fingerprint.

  • Cite this