Computational mutagenesis of E. coli lac repressor: insight into structure-function relationships and accurate prediction of mutant activity

  • Authors:
  • Majid Masso;Kahkeshan Hijazi;Nida Parvez;Iosif I. Vaisman

  • Affiliations:
  • Laboratory for Structural Bioinformatics, George Mason University, Manassas, VA;Laboratory for Structural Bioinformatics, George Mason University, Manassas, VA;Laboratory for Structural Bioinformatics, George Mason University, Manassas, VA;Laboratory for Structural Bioinformatics, George Mason University, Manassas, VA

  • Venue:
  • ISBRA'08 Proceedings of the 4th international conference on Bioinformatics research and applications
  • Year:
  • 2008

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Abstract

A computational mutagenesis methodology that utilizes a four-body,knowledge-based, statistical contact potential is applied toward quantifyingrelative changes (residual scores) to sequence-structure compatibility in E. colilac repressor due to single amino acid residue substitutions. We show that theseresidual scores correlate well with experimentally measured relative changes inprotein activity caused by the mutations. The approach also yields a measure ofenvironmental perturbation at every residue position in the protein caused bythe mutation (residual profile). Supervised learning with a decision tree algorithm,utilizing the residual profiles of over 4000 experimentally evaluated mutantsfor training, classifies the mutants based on activity with nearly 79% accuracywhile achieving 0.80 area under the receiver operating characteristic curve.A trained decision tree model is subsequently used to infer the levels of activityfor all remaining unexplored lac repressor mutants.