title: Control of lipase enantioselectivity by engineering the substrate binding site and access channel.
abstract: Lipase from Burkholderia cepacia (BCL) has proven to be a very useful biocatalyst for the resolution of 2-substituted racemic acid derivatives, which are important chiral building blocks. Our previous work showed that enantioselectivity of the wild-type BCL could be improved by chemical engineering of the substrate's molecular structure. From this earlier study, three amino acids (L17, V266 and L287) were proposed as targets for mutagenesis aimed at tailoring enzyme enantioselectivity. In the present work, a small library of 57 BCL single mutants targeted on these three residues was constructed and screened for enantioselectivity towards (R,S)-2-chloro ethyl 2-bromophenylacetate. This led to the fast isolation of three single mutants with a remarkable tenfold enhanced or reversed enantioselectivity. Analysis of substrate docking and access trajectories in the active site was then performed. From this analysis, the construction of 13 double mutants was proposed. Among them, an outstanding improved mutant of BCL was isolated that showed an E value of 178 and a 15-fold enhanced specific activity compared to the parental enzyme; thus, this study demonstrates the efficiency of the semirational engineering strategy.
authors.affiliation: Université de Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, 31077 Toulouse, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Lafaquière
authors.forename: Sophie
authors.initials: S
authors.lastname: Barbe
authors.forename: Sophie
authors.initials: S
authors.lastname: Puech-Guenot
authors.forename: David
authors.initials: D
authors.lastname: Guieysse
authors.forename: Juan
authors.initials: J
authors.lastname: Cortés
authors.forename: Pierre
authors.initials: P
authors.lastname: Monsan
authors.forename: Thierry
authors.initials: T
authors.lastname: Siméon
authors.forename: Isabelle
authors.initials: I
authors.lastname: André
authors.forename: Magali
authors.initials: M
authors.lastname: Remaud-Siméon
mesh_terms: D000085:Acetates / Q000737:chemistry; D001665:Binding Sites; D020134:Catalytic Domain; D008049:Lipase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D015394:Molecular Structure; D016297:Mutagenesis, Site-Directed; D011487:Protein Conformation; D015202:Protein Engineering / Q000379:methods*; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D000085:Acetates; D008049:Lipase