Cloning and characterization of brnQ, a gene encoding a low-affinity, branched-chain amino acid carrier in Lactobacillus delbrdückii subsp. lactic DSM7290

1995 ◽  
Vol 249 (6) ◽  
pp. 682-690 ◽  
Author(s):  
Klaus Stucky ◽  
Anja Hagting ◽  
Jargen R. Klein ◽  
Hugo Matern ◽  
Bernhard Henrich ◽  
...  
Keyword(s):  
Amino Acid ◽  
Gene Encoding ◽  
Branched Chain Amino Acid ◽  
Branched Chain ◽  
Amino Acid Carrier

Crystallographic characterization of the (R)-selective amine transaminase fromAspergillus fumigatus

2014 ◽  
Vol 70 (4) ◽  
pp. 1086-1093 ◽  
Author(s):  
Maren Thomsen ◽  
Lilly Skalden ◽  
Gottfried J. Palm ◽  
Matthias Höhne ◽  
Uwe T. Bornscheuer ◽  
...  
Keyword(s):  
Amino Acid ◽  
Active Sites ◽  
Free Form ◽  
Detailed Knowledge ◽  
Branched Chain Amino Acid ◽  
Sad Phasing ◽  
Branched Chain ◽  
The Stability ◽  
Optically Pure

The importance of amine transaminases for producing optically pure chiral precursors for pharmaceuticals and chemicals has substantially increased in recent years. The X-ray crystal structure of the (R)-selective amine transaminase from the fungusAspergillus fumigatuswas solved by S-SAD phasing to 1.84 Å resolution. The refined structure at 1.27 Å resolution provides detailed knowledge about the molecular basis of substrate recognition and conversion to facilitate protein-engineering approaches. The protein forms a homodimer and belongs to fold class IV of the pyridoxal-5′-phosphate-dependent enzymes. Both subunits contribute residues to form two active sites. The structure of the holoenzyme shows the catalytically important cofactor pyridoxal-5′-phosphate bound as an internal aldimine with the catalytically responsible amino-acid residue Lys179, as well as in its free form. A long N-terminal helix is an important feature for the stability of this fungal (R)-selective amine transaminase, but is missing in branched-chain amino-acid aminotransferases and D-amino-acid aminotransferases.

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