Chromobacterium violaceum ω-transaminase variant Trp60Cys shows increased specificity for (S)-1-phenylethylamine and 4'-substituted acetophenones, and follows Swain-Lupton parameterisation.
For biocatalytic production of pharmaceutically important chiral amines the ω-transaminase enzymes have proven useful. Engineering of these enzymes has to some extent been accomplished by rational design, but mostly by directed evolution. By use of a homology model a key point mutation in Chromobacterium violaceum ω-transaminase was found upon comparison with engineered variants from homologous enzymes. The variant Trp60Cys gave increased specificity for (S)-1-phenylethylamine (29-fold) and 4'-substituted acetophenones (∼5-fold). To further study the effect of the mutation the reaction rates were Swain-Lupton parameterised. On comparison with the wild type, reactions of the variant showed increased resonance dependence; this observation together with changed pH optimum and cofactor dependence suggests an altered reaction mechanism.
KTH Royal Institute of Technology, Division of Biochemistry, School of Biotechnology, AlbaNova University Centre, SE-106 91 Stockholm, Sweden.
Karim Engelmark
KE
Cassimjee
Maria Svedendahl
MS
Humble
Henrik
H
Land
Vahak
V
Abedi
Per
P
Berglund
D000098:Acetophenones / Q000378:metabolism*; D002861:Chromobacterium / Q000201:enzymology* / Q000235:genetics; D010627:Phenethylamines / Q000378:metabolism*; D017354:Point Mutation; D013379:Substrate Specificity; D000637:Transaminases / Q000235:genetics* / Q000378:metabolism*
D000098:Acetophenones; D010627:Phenethylamines; D000637:Transaminases; C033198:1-phenethylamine