Chromobacterium violaceum ω-transaminase variant Trp60Cys shows increased specificity for (S)-1-phenylethylamine and 4'-substituted acetophenones, and follows Swain-Lupton parameterisation.

Karim Engelmark Cassimjee, Maria Svedendahl Humble, Henrik Land, Vahak Abedi, Per Berglund

KTH Royal Institute of Technology, Division of Biochemistry, School of Biotechnology, AlbaNova University Centre, SE-106 91 Stockholm, Sweden.

Organic & biomolecular chemistry 2012 Jul 28

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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.

Citation

Karim Engelmark Cassimjee, Maria Svedendahl Humble, Henrik Land, Vahak Abedi, Per Berglund. Chromobacterium violaceum ω-transaminase variant Trp60Cys shows increased specificity for (S)-1-phenylethylamine and 4'-substituted acetophenones, and follows Swain-Lupton parameterisation. Organic & biomolecular chemistry. 2012 Jul 28;10(28):5466-70