title: Engineering a Lysine-ON Riboswitch for Metabolic Control of Lysine Production in Corynebacterium glutamicum.
abstract: Riboswitches are natural RNA elements that regulate gene expression by binding a ligand. Here, we demonstrate the possibility of altering a natural lysine-OFF riboswitch from Eschericia coli (ECRS) to a synthetic lysine-ON riboswitch and using it for metabolic control. To this end, a lysine-ON riboswitch library was constructed using tetA-based dual genetic selection. After screening the library, the functionality of the selected lysine-ON riboswitches was examined using a report gene, lacZ. Selected lysine-ON riboswitches were introduced into the lysE gene (encoding a lysine transport protein) of Corynebacterium glutamicum and used to achieve dynamic control of lysine transport in a recombinant lysine-producing strain, C. glutamicum LPECRS, which bears a deregulated aspartokinase and a lysine-OFF riboswitch for dynamic control of the enzyme citrate synthase. Batch fermentation results of the strains showed that the C. glutamicum LPECRS strain with an additional lysine-ON riboswitch for the control of lysE achieved a 21% increase in the yield of lysine compared to that of the C. glutamicum LPECRS strain and even a 89% increase in yield compared to that of the strain with deregulated aspartokinase. This work provides a useful approach to generate lysine-ON riboswitches for C. glutamicum metabolic engineering and demonstrates for the first time a synergetic effect of lysine-ON and -OFF riboswitches for improving lysine production in this industrially important microorganism. The approach can be used to dynamically control other genes and can be applied to other microorganisms.
authors: Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology , Denickestrasse 15, D-21073 Hamburg, Germany.
authors: Li-Bang
authors: LB
authors: Zhou
authors: Institute of Bioprocess and Biosystems Engineering, Hamburg University of Technology , Denickestrasse 15, D-21073 Hamburg, Germany.
authors: An-Ping
authors: AP
authors: Zeng
mesh_terms: D048230:Corynebacterium glutamicum / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics*; D008239:Lysine / Q000096:biosynthesis / Q000235:genetics; D060847:Metabolic Engineering / Q000379:methods*; D058928:Riboswitch / Q000235:genetics*
chemical_list: D058928:Riboswitch; D008239:Lysine
keywords: Corynebacterium glutamicum; lysine production; metabolic control; synthetic lysine-ON riboswitch; tetA dual genetic selection