Ca. Shaw-reid et al., Flux through the tetrahydrodipicolinate succinylase pathway is dispensablefor L-lysine production in Corynebacterium glutamicum, APPL MICR B, 51(3), 1999, pp. 325-333
The N-succinyl-LL-diaminopimelate desuccinylase gene (dapE) in the four-ste
p succinylase branch of the L-lysine biosynthetic pathway of Corynebacteriu
m glutamicum was disrupted via marker-exchange mutagenesis to create a muta
nt strain that uses only the onestep meso-diaminopimelate dehydrogenase bra
nch to overproduce lysine. This mutant strain grew and utilized glucose fro
m minimal medium at the same rate as the parental strain. In addition, the
dapE(-) strain produced lysine at the same rate as its parent strain. Trans
formation of the parental and dapE(-) strains with the amplified meso-diami
nopimelate dehydrogenase gene (ddh) on a plasmid did not affect lysine prod
uction in either strain, despite an eightfold amplification of the activity
of the enzyme. These results indicate that the four-step succinylase pathw
ay is dispensable for lysine overproduction in shake-flask culture. In addi
tion, the one-step meso-diaminopimelate dehydrogenase pathway does not limi
t lysine flux in Corynebacterium under these conditions.