Stereochemistry of the transamination reaction catalyzed by aminodeoxychorismate lyase from Escherichia coli: close relationship between fold type and stereochemistry.
Aminodeoxychorismate lyase is a pyridoxal 5'-phosphate-dependent enzyme that converts 4-aminodeoxychorismate to pyruvate and p-aminobenzoate, a precursor of folic acid in bacteria. The enzyme exhibits significant sequence similarity to two aminotransferases, D-amino acid aminotransferase and branched-chain L-amino acid aminotransferase. In the present study, we have found that aminodeoxychorismate lyase catalyzes the transamination between D-alanine and pyridoxal phosphate to produce pyruvate and pyridoxamine phosphate. L-Alanine and other D- and L-amino acids tested were inert as substrates of transamination. The pro-R hydrogen of C4' of pyridoxamine phosphate was stereospecifically abstracted during the reverse half transamination from pyridoxamine phosphate to pyruvate. Aminodeoxychorismate lyase is identical to D-amino acid aminotransferase and branched-chain L-amino acid aminotransferase in the stereospecificity of the hydrogen abstraction, and differs from all other pyridoxal enzymes that catalyze pro-S hydrogen transfer. Aminodeoxychorismate lyase is the first example of a lyase that catalyzes pro-R-specific hydrogen abstraction. The result is consistent with recent X-ray crystallographic findings showing that the topological relationships between the cofactor and the catalytic residue for hydrogen abstraction are conserved among aminodeoxychorismate lyase, D-amino acid aminotransferase and branched-chain L-amino acid aminotransferase [Nakai, T., Mizutani, H., Miyahara, I., Hirotsu, K., Takeda, S., Jhee, K.-H., Yoshimura, T., and Esaki, N. (2000) J. Biochem. 128, 29-38].
Jhee
K H
KH
Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan.
Yoshimura
T
T
Miles
E W
EW
Takeda
S
S
Miyahara
I
I
Hirotsu
K
K
Soda
K
K
Kawata
Y
Y
Esaki
N
N
D000409:Alanine / Q000737:chemistry / Q000378:metabolism; D001051:Apoenzymes / Q000737:chemistry / Q000378:metabolism; D002384:Catalysis; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D019143:Evolution, Molecular; D006859:Hydrogen / Q000378:metabolism; D007700:Kinetics; D008968:Molecular Conformation; D007652:Oxo-Acid-Lyases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D017510:Protein Folding; D011732:Pyridoxal Phosphate / Q000737:chemistry / Q000378:metabolism; D011733:Pyridoxamine / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D019289:Pyruvic Acid / Q000737:chemistry / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D013053:Spectrophotometry; D000637:Transaminases / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D014367:Tryptophan Synthase / Q000378:metabolism; D014368:Tryptophanase / Q000378:metabolism
D001051:Apoenzymes; D011994:Recombinant Proteins; D011732:Pyridoxal Phosphate; D011733:Pyridoxamine; D006859:Hydrogen; D019289:Pyruvic Acid; D000637:Transaminases; D007652:Oxo-Acid-Lyases; C066600:aminodeoxychorismate lyase; D014368:Tryptophanase; D014367:Tryptophan Synthase; D000409:Alanine; C010627:pyridoxamine phosphate