Antimicrobial activity of omwaprin, a new member of the waprin family of snake venom proteins

Nair, D. G., Fry, B. G., Alewood, P. F., Kumar, P. P. and Kini, R. M. (2007) Antimicrobial activity of omwaprin, a new member of the waprin family of snake venom proteins. Biochemical Journal, 401 1: 93-104. doi:10.1042/BJ20060318


Author Nair, D. G.
Fry, B. G.
Alewood, P. F.
Kumar, P. P.
Kini, R. M.
Title Antimicrobial activity of omwaprin, a new member of the waprin family of snake venom proteins
Journal name Biochemical Journal   Check publisher's open access policy
ISSN 0006-2936
Publication date 2007-01-01
Sub-type Article (original research)
DOI 10.1042/BJ20060318
Volume 401
Issue 1
Start page 93
End page 104
Total pages 12
Place of publication London
Publisher Portland Press
Language eng
Subject C1
250302 Biological and Medical Chemistry
780105 Biological sciences
780103 Chemical sciences
Abstract We have isolated and characterized omwaprin, a 50-amino-acid cationic protein from the venom of inland taipan (Oxyuranus microlepidotus). It is a new member of the waprin family of snake venom proteins. A synthetic gene was designed and constructed for expressing the recombinant protein in Escherichia coli. Recombinant omwaprin was used for carrying out functional analyses. The protein is non-toxic to Swiss albino mice at doses of up to 10 mg/kg when administered intraperitoneally. However, it shows selective and dose-dependant antibacterial activity against Gram-positive bacteria. The minimum inhibitory doses were in the range 2-10 mu g for selected species of bacteria in radial diffusion assays. The antibacterial activity is salt-tolerant up to 350 mM NaCl. However, omwaprin lost its antibacterial activity upon reduction and alkylation of its cysteine residues, or upon deletion of six N-terminal amino acid residues, four of which are positively charged. These observations indicate that the three-dimensional structure constrained by four disulfide bonds and the N-terminal residues are essential for its activity. The mechanism of action is via membrane disruption, as shown by scanning electron microscopy. Importantly, omwaprin lacks haemolytic activity on human erythrocytes. This demonstrates the specificity of omwaprin for bacterial membranes. Unlike other reported WAP (whey acidic protein) domain-containing antibacterial proteins, including elafin, EPPIN (epididymal proteinase inhibitor), SWAMI and SWAM2 [single WAP (whey acidic protein) motif proteins 1 and 2] and SLPI (secretory leucocyte proteinase inhibitor), omwaprin shows species-specific activity on the Gram-positive bacteria
Keyword Biochemistry & Molecular Biology
antibacterial protein
antimicrobial protein
inland taipan (Oxyuranus microlepidotus)
omwaprin
snake venom
WAP domain (whey acidic protein domain)
Gram-negative Bacteria
Australian King Brown
Amino-acid-sequence
Cobra Venom
Antibacterial Activity
Pseudechis-australis
Peptides
Purification
Defensins
Inhibitor
Q-Index Code C1
Q-Index Status Confirmed Code

 
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Created: Tue, 19 Feb 2008, 02:21:13 EST