A computational approach to enzyme design: predicting ω-aminotransferase catalytic activity using docking and MM-GBSA scoring

J Chem Inf Model. 2014 Aug 25;54(8):2334-46. doi: 10.1021/ci5002185. Epub 2014 Jul 22.

Abstract

Enzyme design is an important area of ongoing research with a broad range of applications in protein therapeutics, biocatalysis, bioengineering, and other biomedical areas; however, significant challenges exist in the design of enzymes to catalyze specific reactions of interest. Here, we develop a computational protocol using an approach that combines molecular dynamics, docking, and MM-GBSA scoring to predict the catalytic activity of enzyme variants. Our primary focuses are to understand the molecular basis of substrate recognition and binding in an S-stereoselective ω-aminotransferase (ω-AT), which naturally catalyzes the transamination of pyruvate into alanine, and to predict mutations that enhance the catalytic efficiency of the enzyme. The conversion of (R)-ethyl 5-methyl-3-oxooctanoate to (3S,5R)-ethyl 3-amino-5-methyloctanoate in the context of several ω-AT mutants was evaluated using the computational protocol developed in this work. We correctly identify the mutations that yield the greatest improvements in enzyme activity (20-60-fold improvement over wild type) and confirm that the computationally predicted structure of a highly active mutant reproduces key structural aspects of the variant, including side chain conformational changes, as determined by X-ray crystallography. Overall, the protocol developed here yields encouraging results and suggests that computational approaches can aid in the redesign of enzymes with improved catalytic efficiency.

MeSH terms

  • Alanine / chemistry*
  • Alanine Transaminase / chemistry*
  • Alanine Transaminase / genetics
  • Biocatalysis
  • Caprylates / chemistry*
  • Catalytic Domain
  • Crystallography, X-Ray
  • Humans
  • Molecular Dynamics Simulation*
  • Mutation
  • Protein Binding
  • Protein Engineering / methods*
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • Pyruvic Acid / chemistry*
  • Structure-Activity Relationship
  • Substrate Specificity
  • Thermodynamics

Substances

  • Caprylates
  • Pyruvic Acid
  • Alanine Transaminase
  • Alanine