title: Ligand determinants of nisin for its induction activity.
abstract: Nisin has been widely used in the food industry as a safe and natural preservative and has the potential to be used as a biomedicine. Improving nisin production is important for its enormous applications. Nisin A is produced in Lactococcus lactis and its biosynthesis is induced through the regulation of the 2-component system NisKR. In this study, alanine-scanning mutagenesis was applied to study the key structure or AA in nisin for inducing the 2-component system NisKR to regulate downstream gene expression. Assay of β-galactosidase activity revealed that either ring A or ring B was necessary for nisin to induce lacZ reporter gene expression. A substituted first ring formed by Thr2 and Cys7 in S3A instead of ring A (formed by Ser3 and Cys7) fully retained nisin induction activity. Mutation of cationic AA and addition of cationic ions hardly affected nisin induction activity. These results demonstrated that the N-terminal ring structures in nisin were involved in activating NisKR to act as an inducing molecule, whereas the electrostatic force might not contribute to this process. In addition, 2 specific residues were revealed to have potential for improving both nisin induction and antimicrobial activity, which might be used for increasing nisin production.
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China; University of Chinese Academy of Sciences, Beijing 100101, People's Republic of China.
authors.forename: Xiaoxuan
authors.initials: X
authors.lastname: Ge
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China. Electronic address: tengkl@im.ac.cn.
authors.forename: Kunling
authors.initials: K
authors.lastname: Teng
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China; College of Engineering, University of Georgia, Athens 30602.
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China; University of Chinese Academy of Sciences, Beijing 100101, People's Republic of China.
authors.forename: Fangyuan
authors.initials: F
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China; University of Chinese Academy of Sciences, Beijing 100101, People's Republic of China.
authors.forename: Fangfang
authors.initials: F
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China; University of Chinese Academy of Sciences, Beijing 100101, People's Republic of China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, People's Republic of China. Electronic address: zhongj@im.ac.cn.
authors.forename: Jin
authors.initials: J
authors.lastname: Zhong
mesh_terms: D000409:Alanine / Q000235:genetics; D001426:Bacterial Proteins / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D005786:Gene Expression Regulation; D005798:Genes, Bacterial; D017930:Genes, Reporter; D013294:Lactococcus lactis / Q000235:genetics* / Q000378:metabolism*; D008024:Ligands; D016296:Mutagenesis; D009561:Nisin / Q000096:biosynthesis* / Q000737:chemistry*; D020539:Sequence Analysis, Protein; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D008024:Ligands; D009561:Nisin; D001616:beta-Galactosidase; C102526:nisin A; D000409:Alanine
keywords: alanine-scanning mutants; induction activity; lantibiotics; nisin