Identification and characterization of the last two unknown genes, dapC and dapF, in the succinylase branch of the L-lysine biosynthesis of Corynebacterium glutamicum.
The inspection of the complete genome sequence of Corynebacterium glutamicum ATCC 13032 led to the identification of dapC and dapF, the last two unknown genes of the succinylase branch of the L-lysine biosynthesis. The deduced DapF protein of C. glutamicum is characterized by a two-domain structure and a conserved diaminopimelate (DAP) epimerase signature. Overexpression of dapF resulted in an 8-fold increase of the specific epimerase activity. A defined deletion in the dapF gene led to a reduced growth of C. glutamicum in a medium with excess carbon but limited ammonium availability. The predicted DapC protein of C. glutamicum shared 29% identical amino acids with DapC from Bordetella pertussis, the only enzymatically characterized N-succinyl-aminoketopimelate aminotransferase. Overexpression of the dapC gene in C. glutamicum resulted in a 9-fold increase of the specific aminotransferase activity. A C. glutamicum mutant with deleted dapC showed normal growth characteristics with excess carbon and limited ammonium. Even a mutation of the two genes dapC and ddh, interrupting both branches of the split pathway, could be established in C. glutamicum. Overexpression of the dapF or the dapC gene in an industrial C. glutamicum strain resulted in an increased L-lysine production, indicating that both genes might be relevant targets for the development of improved production strains.
Hartmann
Michael
M
Lehrstuhl für Genetik, Universität Bielefeld, Universitätsstrasse 25, D-33615 Bielefeld, Germany.
Tauch
Andreas
A
Eggeling
Lothar
L
Bathe
Brigitte
B
Möckel
Bettina
B
Pühler
Alfred
A
Kalinowski
Jörn
J
D000591:Amino Acid Isomerases / Q000235:genetics* / Q000378:metabolism*; D000595:Amino Acid Sequence; D003352:Corynebacterium / Q000201:enzymology* / Q000235:genetics* / Q000254:growth & development; D003960:Diaminopimelic Acid / Q000378:metabolism*; D020869:Gene Expression Profiling / Q000379:methods; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D008239:Lysine / Q000096:biosynthesis* / Q000235:genetics; D008969:Molecular Sequence Data; D020539:Sequence Analysis, Protein / Q000379:methods; D017386:Sequence Homology, Amino Acid; D051277:Succinyldiaminopimelate Transaminase; D000637:Transaminases / Q000235:genetics* / Q000378:metabolism*
D003960:Diaminopimelic Acid; D000637:Transaminases; D051277:Succinyldiaminopimelate Transaminase; D000591:Amino Acid Isomerases; C042032:diaminopimelate epimerase; D008239:Lysine