title: Genome-wide investigation of aromatic acid transporters in Corynebacterium glutamicum.
abstract: Genome-wide data mining indicated that six genes (ncgl1031, ncgl2302, ncgl2325, ncgl2326, ncgl2922 and ncgl2953) encoding putative transport proteins are involved in uptake of various aromatic compounds that are further degraded through the beta-ketoadipate, gentisate and resorcinol pathways in Corynebacterium glutamicum. The gentisate (GenK/NCgl2922) and vanillate (VanK/NCgl2302) transporters have been identified previously. In this study, physiological functions of the remaining four putative transporters as well as the vanillate transporter (VanK/NCgl2302) were examined by genetic disruption/complementation and uptake assays. Results indicated that ncgl1031 encodes PcaK for 4-hydroxybenzoate and protocatechuate transport, and ncgl2302 encodes VanK for vanillate transport. Genetic studies and uptake assays indicated that both ncgl2325/benK and ncgl2326/benE are involved in benzoate transport in C. glutamicum. When growth rates were compared for two benzoate transporter mutants, benK and benE, a high growth rate was observed for the benE mutant. Sequence alignments revealed that PcaK, VanK, BenK and GenK belong to the major facilitator superfamily (MFS). Modelling of secondary structures based on previously characterized MFS members revealed that NCgl1031, NCgl2302, NCgl2325 and NCgl2922 are typical 12 helix transmembrane proteins but NCgl2326 contains only 11 alpha-helices. Thus the functionally identified NCgl2326 belongs to a novel type of benzoate transporters. Attempts to identify the phenotype of a hydK/ncgl2953 mutant failed, so the function of ncgl2953 remains unclear.
authors.affiliation: Graduate University of Chinese Academy of Sciences, Beijing, 100049, China.|State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100080, China.
authors.forename: Muhammad Tausif
authors.initials: MT
authors.lastname: Chaudhry
authors.affiliation: Graduate University of Chinese Academy of Sciences, Beijing, 100049, China.|State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100080, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100080, China.
authors.forename: Xi-Hui
authors.initials: XH
authors.lastname: Shen
authors.affiliation: Lehrstuhl für Biochemie der Pflanzen, Ruhr Universität, Bochum, Germany.
authors.forename: Ansgar
authors.initials: A
authors.lastname: Poetsch
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100080, China.
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, Beijing, 100080, China.
authors.forename: Shuang-Jiang
authors.initials: SJ
authors.lastname: Liu
mesh_terms: D001565:Benzoates / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics* / Q000502:physiology; D048230:Corynebacterium glutamicum / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D023061:Gene Order; D005816:Genetic Complementation Test; D016680:Genome, Bacterial / Q000235:genetics*; D006841:Hydrocarbons, Aromatic / Q000378:metabolism*; D062385:Hydroxybenzoates / Q000378:metabolism; D010226:Parabens / Q000378:metabolism; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid; D014641:Vanillic Acid / Q000378:metabolism
chemical_list: D001565:Benzoates; D002352:Carrier Proteins; D006841:Hydrocarbons, Aromatic; D062385:Hydroxybenzoates; D010226:Parabens; C009091:protocatechuic acid; D014641:Vanillic Acid; C038193:4-hydroxybenzoic acid