title: Ribosome binding site libraries and pathway modules for shikimic acid synthesis with Corynebacterium glutamicum.
abstract: BACKGROUND
  The shikimic acid (SA) pathway is a fundamental route to synthesize aromatic building blocks for cell growth and metabolic processes, as well as for fermentative production of various aromatic compounds. Genes encoding enzymes of SA pathway are not continuous on genome and they are differently regulated.
  
  
  RESULTS
  In this study, efforts were made to construct continuous genetic modules of SA pathway that are regulated by a same Ptac promoter. Firstly, aro genes [aroG (NCgl2098), aroB (NCgl1559), aroD (NCgl0408) and aroE (NCgl1567)] from Corynebacterium glutamicum and ribosome binding site (RBS) libraries that were tailored for the above genes were obtained, and the strength of each RBS in the 4 libraries was quantified. Secondly, 9 genetic modules were built up from the RBS libraries, a previously characterized ribozyme insulator (RiboJ) and transcriptional promoter (Ptac) and terminator, and aroG, aroB, aroD and aroE. The functionality and efficiency of the constructed genetic modules were evaluated in C. glutamicum by determination of SA synthesis. Results showed that C. glutamicum RES167ΔaroK carrying a genetic module produced 4.3 g/L of SA, which was 54 folds higher compared to that of strain RES167ΔaroK (80 mg/L, without the genetic module) during fermentation in 250-mL flasks. The same strain produced 7.4, and 11.3 g/L of SA during 5-L batch and fed-batch fermentations, respectively, which corresponding to SA molar yields of 0.39 and 0.24 per mole sucrose consumption.
  
  
  CONCLUSIONS
  These results demonstrated that the constructed SA pathway modules are effective in increasing SA synthesis in C. glutamicum, and they might be useful for fermentative production of aromatic compounds derived from SA pathway.
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beichen-Xilu No.1, 100101, Beijing, PR China. icebirdzb@163.com.|University of Chinese Academy of Sciences, 100101, Beijing, PR China. icebirdzb@163.com.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beichen-Xilu No.1, 100101, Beijing, PR China. zhoun@im.ac.cn.
authors.forename: Nan
authors.initials: N
authors.lastname: Zhou
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beichen-Xilu No.1, 100101, Beijing, PR China. liuy@im.ac.cn.
authors.forename: Yi-Ming
authors.initials: YM
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beichen-Xilu No.1, 100101, Beijing, PR China. liu@im.ac.cn.
authors.forename: Chang
authors.initials: C
authors.lastname: Liu
authors.affiliation: CAS Key Laboratory of Microbial Physiology and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, 100101, Beijing, PR China. louchunbo@im.ac.cn.
authors.forename: Chun-Bo
authors.initials: CB
authors.lastname: Lou
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beichen-Xilu No.1, 100101, Beijing, PR China. jiangcy@im.ac.cn.
authors.forename: Cheng-Ying
authors.initials: CY
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beichen-Xilu No.1, 100101, Beijing, PR China. liusj@im.ac.cn.
authors.forename: Shuang-Jiang
authors.initials: SJ
authors.lastname: Liu
mesh_terms: D001665:Binding Sites; D048230:Corynebacterium glutamicum / Q000378:metabolism*; D005285:Fermentation; D053263:Gene Regulatory Networks; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012270:Ribosomes / Q000378:metabolism*; D012765:Shikimic Acid / Q000138:chemical synthesis* / Q000378:metabolism
chemical_list: D012765:Shikimic Acid