First structure of archaeal branched-chain amino acid aminotransferase from Thermoproteus uzoniensis specific for l-amino acids and R-amines

• Published in: Extremophiles : life under extreme conditions 2016-03, Vol.20 (2), p.215-225
• Main Authors: Boyko, Konstantin M., Stekhanova, Tatiana N., Nikolaeva, Alena Yu, Mardanov, Andrey V., Rakitin, Andrey L., Ravin, Nikolai V., Bezsudnova, Ekaterina Yu, Popov, Vladimir O.
• Format: Article
• Language: English
• Subjects: Amines; Amines - chemistry; Amines - metabolism; Amino acids; Amino Acids, Branched-Chain - chemistry; Amino Acids, Branched-Chain - metabolism; Archaeal Proteins - chemistry; Archaeal Proteins - genetics; Archaeal Proteins - metabolism; Bacteria; Biochemistry; Biomedical and Life Sciences; Biotechnology; E coli; Enzyme Stability; Enzymes; Escherichia coli; High temperature; Life Sciences; Microbial Ecology; Microbiology; Organic solvents; Original Paper; Space life sciences; Substrate Specificity; Thermoproteus; Thermoproteus - enzymology; Transaminases - chemistry; Transaminases - genetics; Transaminases - metabolism
• ISSN: 1431-0651; 1433-4909
• DOI: 10.1007/s00792-016-0816-z

The gene TUZN1299 from the genome of the hyperthermophilic archaeon Thermoproteus uzoniensi s encoding a new 32.8 kDa branched-chain amino acid aminotransferase (BCAT) was expressed in Escherichia coli . The recombinant protein TUZN1299 was purified to homogeneity in the PLP-bound form. TUZN1299 was active towards branched-chain amino acids ( l -Val, l -Leu, l -Ile) and showed low but detectable activity toward ( R )-alpha-methylbenzylamine. The enzyme exhibits high-temperature optimum, thermal stability, and tolerance to organic solvents. The structure of an archaeal BCAT called TUZN1299 was solved for the first time (at 2.0 Å resolution). TUZN1299 has a typical BCAT type IV fold, and the organization of its active site is similar to that of bacterial BCATs. However, there are some differences in the amino acid composition of the active site.