Biosynthesis of lysine in plants: evidence for a variant of the known bacterial pathways.
With the aim of elucidating how plants synthesize lysine, extracts prepared from corn, tobacco, Chlamydomonas and soybean were tested and found to lack detectable amounts of N-alpha-acyl-L,L-diaminopimelate deacylase or N-succinyl-alpha-amino-epsilon-ketopimelate-glutamate aminotransaminase, two key enzymes in the central part of the bacterial pathway for lysine biosynthesis. Corn extracts missing two key enzymes still carried out the overall synthesis of lysine when provided with dihydrodipicolinate. An analysis of available plant DNA sequences was performed to test the veracity of the negative biochemical findings. Orthologs of dihydrodipicolinate reductase and diaminopimelate epimerase (enzymes on each side of the central pathway) were readily found in the Arabidopsis thaliana genome. Orthologs of the known enzymes needed to convert tetrahydrodipicolinate to diaminopimelic acid (DAP) were not detected in Arabidopsis or in the plant DNA sequence databases. The biochemical and reinforcing bioinformatics results provide evidence that plants may use a novel variant of the bacterial pathways for lysine biosynthesis.
Hudson
Andre' O
AO
Biotech Center and Department of Plant Biology and Pathology, Rutgers University, 59 Dudley Road, New Brunswick, NJ 08901-8520, USA.
Bless
Christine
C
Macedo
Polliana
P
Chatterjee
Siba P
SP
Singh
Bijay K
BK
Gilvarg
Charles
C
Leustek
Thomas
T
D001419:Bacteria / Q000378:metabolism*; D002262:Carboxy-Lyases / Q000378:metabolism; D003960:Diaminopimelic Acid / Q000378:metabolism; D050746:Dihydrodipicolinate Reductase; D029968:Escherichia coli Proteins / Q000378:metabolism; D008239:Lysine / Q000096:biosynthesis*; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000378:metabolism; D010802:Phylogeny; D010944:Plants / Q000378:metabolism*
D029968:Escherichia coli Proteins; D003960:Diaminopimelic Acid; D050746:Dihydrodipicolinate Reductase; D044925:Oxidoreductases Acting on CH-CH Group Donors; D002262:Carboxy-Lyases; C489812:LysA protein, E coli; D008239:Lysine