Crystal structure and reactivity of YbdL from Escherichia coli identify a methionine aminotransferase function.
The ybdL gene of Escherichia coli codes for a protein of unknown function. Sequence analysis showed moderate homology to several vitamin B(6) dependent enzymes, suggesting that it may bind pyridoxal-5'-phosphate. The structure analysis of YbdL to 2.35 A resolution by protein crystallography verifies that it is a PLP dependent enzyme of fold type I, the typical aspartate aminotransferase fold. The active site contains a bound pyridoxal-5'-phosphate, covalently attached to the conserved active site lysine residue Lys236. The pattern of conserved amino acids in the putative substrate binding pocket of the enzyme reveals that it is most closely related to a hyperthermophilic aromatic residue aminotransferase from the archeon Pyrococcus horikoshii. Activity tests with 10 amino acids as amino-donors reveal, however, a preference for Met, followed by His and Phe, results which can be rationalized by modelization studies.
Dolzan
Manuela
M
Architecture et Fonction des Macromolécules Biologiques, UMR 6098, CNRS and Universités d'Aix-Marseille I and II, 31 chemin J. Aiguier, F-13402 Marseille Cedex 20, France.
Johansson
Kenth
K
Roig-Zamboni
Véronique
V
Campanacci
Valérie
V
Tegoni
Mariella
M
Schneider
Gunter
G
Cambillau
Christian
C
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D017124:Conserved Sequence; D018360:Crystallography, X-Ray; D017931:DNA Primers; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000378:metabolism*; D007700:Kinetics; D008715:Methionine / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011732:Pyridoxal Phosphate / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D012680:Sensitivity and Specificity; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D000637:Transaminases / Q000737:chemistry* / Q000378:metabolism*
D017931:DNA Primers; D029968:Escherichia coli Proteins; D011994:Recombinant Proteins; D011732:Pyridoxal Phosphate; D008715:Methionine; D000637:Transaminases; C488967:YbdL protein, E coli