title: Expression of a modified antimicrobial peptide BhSGAMP-1-S (Bradysia hygida) in Escherichia coli and characterization of its activity.
abstract: OBJECTIVE
  Bradysia hygida salivary glands antimicrobial peptide 1 (BhSGAMP-1) is one of the antimicrobial peptides involved in a preventive mechanism of defense of the fly Bradysia hygida. To know better about the molecular characterization of this antimicrobial peptide, we expressed and purified the modified BhSGAMP-1-S and investigated its antimicrobial activity.
  
  
  METHODS
  We synthesized the gene of BhSGAMP-1-S designed with preferred codons of Escherichia coli and expressed it as a fusion protein in E. coli TB1 by using pMAL-c2X as vector. We purified the fusion protein using amylase resin affinity chromatography. In addition, we cleaved the fusion protein by enterokinase and the released recombinant BhSGAMP-1-S was separated by size exclusion chromatography, then followed by reversed-phase high performance liquid chromatography. We analyzed the antimicrobial activities of the purified recombinant BhSGAMP-1-S by bioassays.
  
  
  RESULTS
  The fusion protein was mostly expressed in soluble form under the optimized conditions. The recombinant BhSGAMP-1-S was produced with a pure yield of 0.38 mg/100 mL culture medium. Antimicrobial assays demonstrated that the recombinant BhSGAMP-1-S was active against several Gram-positive and Gram-negative bacteria and fungi.
  
  
  CONCLUSIONS
  It appears to be the first successful production of the recombinant BhSGAMP-1-S from fly Bradysia hygida. Data presented here confirm that the recombinant BhSGAMP-1-S is now ready for further studying and characterizing their antimicrobial properties.
authors.affiliation: Key Laboratory of Plant Protection Resources and Pest Management, Ministry of Education, China. wangjue1103@hotmail.com
authors.forename: Jue
authors.initials: J
authors.lastname: Wang
authors.forename: Qiurong
authors.initials: Q
authors.lastname: Gao
authors.forename: Qiang
authors.initials: Q
authors.lastname: Liu
authors.forename: Linping
authors.initials: L
authors.lastname: Xiang
authors.forename: Yuqin
authors.initials: Y
authors.lastname: Wang
authors.forename: Dun
authors.initials: D
authors.lastname: Wang
mesh_terms: D000818:Animals; D000890:Anti-Infective Agents / Q000378:metabolism* / Q000494:pharmacology*; D004175:Diptera / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D006090:Gram-Negative Bacteria / Q000187:drug effects; D006094:Gram-Positive Bacteria / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D010455:Peptides / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology*
chemical_list: D000890:Anti-Infective Agents; D010455:Peptides