title: [Expression, purification and hIgG-binding activity identification of truncated Streptococcus suis factor H-binding protein].
abstract: OBJECTIVE
  To construct a prokaryotic expression vector of the His-tagged truncated factor H-binding protein (Fhb) fragments, Fhb-N (amino acids 45-344aa) and Fhb-C (amino acids 345-644aa), of Streptococcus suis serotype 2, express it in E.coli BL21 (DE3) in order to acquire high-purity recombinant protein, and finally identify the binding activity with human serum IgG (hIgG).
  
  
  METHODS
  Fhb-N gene and Fhb-C gene were amplified using the primers designed according to 05ZYH33 genome sequences and cloned into the expression vector pET28a⁺ to construct recombinant plasmids. The plasmids were transformed into E.coli BL21 (DE3) and induced to express by IPTG. The recombinant proteins were purified by nickel affinity chromatography and identified by Western blotting. The hIgG was purified from human serum by HiTrap protein G HP column in accordance with the manufacturer's instructions. In addition, the specific binding to hIgG was identified by Western blotting and biolayer Interferometry (BLI).
  
  
  RESULTS
  The prokaryotic expression vector of His-Fhb-N and His-Fhb-C was constructed, and the target proteins were expressed, purified and identified. The specific binding activity with hIgG was identified and the binding region was found located on the Fhb-N(45-344aa).
  
  
  CONCLUSIONS
  His-Fhb-N can specifically bind to hIgG, which will help us to further study the role of Fhb-hIgG interaction in the pathogenesis of Streptococcus suis.
authors.affiliation: School of Graduates, Anhui Medical University, Hefei 230032; State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing 100071, China.
authors.forename: Xueqin
authors.initials: X
authors.lastname: Li
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing 100071, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing 100071, China.
authors.forename: Yaya
authors.initials: Y
authors.lastname: Pian
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing 100071, China.
authors.forename: Yuling
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: School of Graduates, Anhui Medical University, Hefei 230032; State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing 100071, China.
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing 100071, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Yuan
authors.affiliation: Yanjing Medical College, Capital Medical University, Beijing 101300, China.
authors.forename: Chunyue
authors.initials: C
authors.lastname: Huo
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D001665:Binding Sites / Q000235:genetics / Q000276:immunology; D015153:Blotting, Western; D004926:Escherichia coli / Q000235:genetics; D015870:Gene Expression; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology* / Q000378:metabolism; D010446:Peptide Fragments / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D011485:Protein Binding / Q000276:immunology; D011994:Recombinant Proteins / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D012703:Serotyping; D017011:Streptococcus suis / Q000145:classification / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D007074:Immunoglobulin G; D010446:Peptide Fragments; D011994:Recombinant Proteins