title: Stereochemistry of lysine formation by meso-diaminopimelate decarboxylase from wheat germ: use of 1H-13C NMR shift correlation to detect stereospecific deuterium labeling.
abstract: The stereochemical course of the wheat germ meso-diaminopimelate (DAP) decarboxylase reaction is compared to that of the decarboxylase isolated from Bacillus sphaericus, which has been reported to proceed with an unusual inversion of configuration [Asada, Y., Tanizawa, K., Sawada, S., Suzuki, T., Misono, H., & Soda, K. (1981) Biochemistry 20, 6881-6886]. Reaction of each enzyme with either unlabeled diaminopimelic acid in D2O or [2,6-2H2]diaminopimelic acid in H2O gave stereospecifically deuterium-labeled lysine samples that were derivatized with (-)-camphanoyl chloride and diazomethane. Analysis by two-dimensional 1H-13C heteronuclear NMR shift correlation spectroscopy with 2H decoupling confirmed the stereochemistry of the B. sphaericus enzyme reaction and showed that the eukaryotic wheat germ meso-DAP decarboxylase also operates with inversion of configuration. This suggests similar mechanisms for the prokaryotic and eukaryotic enzymes and contrasts the retention mode observed with other pyridoxal phosphate dependent alpha-decarboxylases.
mesh_terms: D001426:Bacterial Proteins; D002262:Carboxy-Lyases / Q000378:metabolism*; D003903:Deuterium; D007553:Isotope Labeling; D008239:Lysine / Q000096:biosynthesis*; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D012639:Seeds / Q000201:enzymology*; D013237:Stereoisomerism; D014908:Triticum / Q000201:enzymology
chemical_list: D001426:Bacterial Proteins; D003903:Deuterium; D002262:Carboxy-Lyases; C079912:LysA protein, Bacteria; C020031:diaminopimelic acid decarboxylase; D008239:Lysine