title: Biotechnical paving of recombinant enterocin A as the candidate of anti-Listeria agent.
abstract: BACKGROUND
  Enterocin A is a classic IIa bacteriocin isolated firstly from Enterococcus faecium CTC492 with selective antimicrobial activity against Listeria strains. However, the application of enterocin A as an anti-Listeria agent has been limited due to its very low native yield. The present work describes high production of enterocin A through codon optimization strategy and its character study.
  
  
  RESULTS
  The gene sequence of enterocin A was optimized based on preferential codon usage in Pichia pastoris to increase its expression efficiency. The highest anti-Listeria activity reached 51,200 AU/ml from 180 mg/l of total protein after 24 h of induction in a 5-L fermenter. Recombinant enterocin A (rEntA), purified by gel filtration chromatography, showed very strong activity against Listeria ivanovii ATCC 19119 with a low MIC of 20 ng/ml. In addition, the rEntA killed over 99% of tested L. ivanovii ATCC19119 within 4 h when exposed to 4 × MIC (80 ng/ml). Moreover, it showed high stability under a wide pH range (2-10) and maintained full activity after 1 h of treatment at 80°C within a pH range of 2-8. Its antimicrobial activity was enhanced at 25 and 50 mM NaCl, while 100-400 mM NaCl had little effect on the bactericidal ability of rEntA.
  
  
  CONCLUSIONS
  The EntA was successfully expressed in P. pastoris, and this feasible system could pave the pre-industrial technological path of rEntA as a competent candidate as an anti-Listeria agent. Furthermore, it showed high stability under wide ranges of conditions, which could be potential as the new candidate of anti-Listeria agent.
authors.forename: Xiaoyuan
authors.initials: X
authors.lastname: Hu
authors.forename: Ruoyu
authors.initials: R
authors.lastname: Mao
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.forename: Da
authors.initials: D
authors.lastname: Teng
authors.forename: Xiumin
authors.initials: X
authors.lastname: Wang
authors.forename: Di
authors.initials: D
authors.lastname: Xi
authors.affiliation: Key Laboratory of Feed Biotechnology, Ministry of Agriculture, Beijing 100081, China. hjz@fjnu.edu.cn.
authors.forename: Jianzhong
authors.initials: J
authors.lastname: Huang
authors.forename: Jianhua
authors.initials: J
authors.lastname: Wang
mesh_terms: D001430:Bacteriocins / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism / Q000494:pharmacology*; D002850:Chromatography, Gel; D020536:Enzyme Activators / Q000378:metabolism; D015870:Gene Expression; D005822:Genetic Vectors; D006863:Hydrogen-Ion Concentration; D008087:Listeria / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010843:Pichia / Q000235:genetics / Q000378:metabolism; D055550:Protein Stability; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology; D017422:Sequence Analysis, DNA; D012965:Sodium Chloride / Q000378:metabolism; D013696:Temperature
chemical_list: D001430:Bacteriocins; D020536:Enzyme Activators; D011994:Recombinant Proteins; C107799:enterocin A; D012965:Sodium Chloride