Exploring the allosteric mechanism of dihydrodipicolinate synthase by reverse engineering of the allosteric inhibitor binding sites and its application for lysine production.
Dihydrodipicolinate synthase (DHDPS, EC 4.2.1.52) catalyzes the first committed reaction of L-lysine biosynthesis in bacteria and plants and is allosterically regulated by L-lysine. In previous studies, DHDPSs from different species were proved to have different sensitivity to L-lysine inhibition. In this study, we investigated the key determinants of feedback regulation between two industrially important DHDPSs, the L-lysine-sensitive DHDPS from Escherichia coli and L-lysine-insensitive DHDPS from Corynebacterium glutamicum, by sequence and structure comparisons and site-directed mutation. Feedback inhibition of E. coli DHDPS was successfully alleviated after substitution of the residues around the inhibitor's binding sites with those of C. glutamicum DHDPS. Interestingly, mutagenesis of the lysine binding sites of C. glutamicum DHDPS according to E. coli DHDPS did not recover the expected feedback inhibition but an activation of DHDPS by L-lysine, probably due to differences in the allosteic signal transduction in the DHDPS of these two organisms. Overexpression of L-lysine-insensitive E. coli DHDPS mutants in E. coli MG1655 resulted in an improvement of L-lysine production yield by 46 %.
Department of Biopharmaceutic Engineering, School of Chemical Engineering and Technology, Tianjin University, 92 Weijin Road, Nankai District, Tianjin 300072, China.
Feng
F
Geng
Zhen
Z
Chen
Ping
P
Zheng
Jibin
J
Sun
An-Ping
AP
Zeng
D000494:Allosteric Regulation; D000595:Amino Acid Sequence; D001665:Binding Sites; D048230:Corynebacterium glutamicum / Q000201:enzymology*; D020536:Enzyme Activators / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology*; D006836:Hydro-Lyases / Q000235:genetics* / Q000378:metabolism*; D008239:Lysine / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D015202:Protein Engineering; D016415:Sequence Alignment
D020536:Enzyme Activators; D004791:Enzyme Inhibitors; D050505:Mutant Proteins; D006836:Hydro-Lyases; C020040:4-hydroxy-tetrahydrodipicolinate synthase; D008239:Lysine