Functional characterization of PLP fold type IV transaminase with a mixed type of activity from Haliangium ochraceum

Publication date: Available online 19 March 2019Source: Biochimica et Biophysica Acta (BBA) - Proteins and ProteomicsAuthor(s): Yulia S. Zeifman, Konstantin M. Boyko, Alena Yu Nikolaeva, Vladimir I. Timofeev, Tatiana V. Rakitina, Vladimir O. Popov, Ekaterina Yu BezsudnovaAbstractPyridoxal-5′-phosphate (PLP)-dependent transaminases are industrially important enzymes catalyzing the stereoselective amination of ketones and keto acids. Transaminases of PLP fold type IV are characterized by (R)- or (S)-stereoselective transfer of amino groups, depending on the substrate profile of the enzyme. PLP fold type IV transaminases include branched-chain amino acid transaminases (BCATs), D-amino acid transaminases and (R)-amine:pyruvate transaminases. Recently, transaminases with a mixed type of activity were identified and characterized. Here, we report biochemical and structural characterization of a transaminase from myxobacterium Haliangium ochraceum (Hoch3033), which is active towards keto analogs of branched-chain amino acids (specific substrates for BCATs) and (R)-(+)-α-methylbenzylamine (specific substrate for (R)-amine:pyruvate transaminases). The enzyme is characterized by an alkaline pH optimum (pH 10.0–10.5) and a tolerance to high salt concentrations (up to 2 M NaCl). The structure of Hoch3033 was determined at 2.35 Å resolution. The overall fold of the enzyme was similar to those of known enzymes of PLP fold type IV. The mixed type of activity of Hoch3033 was impl...
Source: Biochimica et Biophysica Acta (BBA) Proteins and Proteomics - Category: Biochemistry Source Type: research