Rational Protein Design of Thdp-Dependent Enzymes-Engineering Stereoselectivity.
Gocke, D., Walter, L., Gauchenova, K., Kolter, G., Knoll, M., Berthold, C.L., Schneider, G., Pleiss, J., Muller, M., Pohl, M.(2008) Chembiochem 9: 406
- PubMed: 18224647 
- DOI: https://doi.org/10.1002/cbic.200700598
- Primary Citation of Related Structures:  
2V3W - PubMed Abstract: 
Benzoylformate decarboxylase (BFD) from Pseudomonas putida is an exceptional thiamin diphosphate-dependent enzyme, as it catalyzes the formation of (S)-2-hydroxy-1-phenylpropan-1-one from benzaldehyde and acetaldehyde. This is the only currently known S-selective reaction (92 % ee) catalyzed by this otherwise R-selective class of enzymes. Here we describe the molecular basis of the introduction of S selectivity into ThDP-dependent decarboxylases. By shaping the active site of BFD through the use of rational protein design, structural analysis, and molecular modeling, optimal steric stabilization of the acceptor aldehyde in a structural element called the S pocket was identified as the predominant interaction for adjusting stereoselectivity. Our studies revealed Leu461 as a hot spot for stereoselectivity in BFD. Exchange to alanine and glycine resulted in variants that catalyze the S-stereoselective addition of larger acceptor aldehydes, such as propanal with benzaldehyde and its derivatives-a reaction not catalyzed by the wild-type enzyme. Crystal structure analysis of the variant BFDL461A supports the modeling studies.
Organizational Affiliation: 
Institute of Molecular Enzyme Technology, Heinrich-Heine University Düsseldorf, 52426 Jülich, Germany.