Converting a fatty acid binding protein to an artificial transaminase: novel catalysts by chemical and genetic modification of a protein cavity

Despite the widespread use of enzymes in synthetic applications, their "nat ive" characteristics are often insufficient for many chemical transformatio ns. To meet this challenge we have used protein cavities for the design of new biocatalysts. A pyridoxamine derivative (PX) was chemically tethered wi thin the spacious cavity of intestinal fatty acid binding protein (IFABP). The cysteine residue, which anchors the cofactor of the artificial transami nase IFABP-PX, can be placed in different regions by site-directed mutagene sis. Catalytic reactions with high enantioselectivities (up to 94% ee) and varying substrate specificity of the transamination of a-keto and amino aci ds were achieved. IFABP-PX mutants were further optimized by introducing ly sine residues in order to mimic the active site of native transaminases. (C ) 2001 Elsevier Science B.V. All rights reserved.