Expression and structure/function relationships of human defensin 5

Nava Chapnik, Anat Levit, Masha Y. Niv, Oren Froy*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


The innate immunity utilizes a battery of broad-spectrum antibacterial cationic polypeptides (3-5 kDa), among them defensins. In humans, defensins are the first line of defense against pathogens and their expression has been implicated in several diseases. The antibacterial activity of defensins is generally ascribed to their overall positive charge, which enables them to disrupt bacterial membrane integrity and function, but their active surface has not been fully elucidated. To perform structural and functional assays, an efficient, highyield, easy-to-use expression and purification system must be established. Up to now, most efforts to obtain larger quantities of active recombinant defensins have been only moderately successful. Herein, we report the establishment of an efficient, high-yield expression and purification system for human defensin 5 (HD-5). Using site-directed mutagenesis, we pinpoint several arginine residues and Y27 as important for HD-5 antibacterial activity. Our expression and purification system can be harnessed for structure/activity relationship studies of defensins in particular and small polypeptides in general.

Original languageAmerican English
Pages (from-to)1703-1710
Number of pages8
JournalApplied Biochemistry and Biotechnology
Issue number7
StatePublished - Apr 2012


  • Defensins
  • Expression
  • HD-5
  • Site-directed mutagenesis


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