A single residue influences the reaction mechanism of ammonia lyases and mutases.
All ways lead to Rome? Computer modeling and kinetic measurements identified a distinct residue in Phe/Tyr ammonia lyases (PAL/TAL) which controls whether the Friedel-Crafts or an E(1)cB reaction mechanism takes place. Hence, Glu484 in pcPAL favors the Friedel-Crafts reaction (see picture, MIO = 4-methylidene imidazol-5-one) whereas an Asn in TAL gives an elimination reaction. These mechanistic investigations also reveal activity of a PAL mutant and a TAL towards an amino alcohol.
Bartsch
Sebastian
S
Institute of Biochemistry, Dept. of Biotechnology & Enzyme Catalysis, Greifswald University, Felix-Hausdorff-Strasse 4, 17487 Greifswald, Germany.
Bornscheuer
Uwe T
UT