Oral Presentation 6th Modern Solid Phase Peptide Synthesis & Its Applications Symposium 2017

Synthesis of cysteine-rich antimicrobial peptides and proteins (#2)

Margaret Brimble 1
  1. The University of Auckland, Auckland, New Zealand

Due to the on-going global expansion of antimicrobial resistant (AMR) infections, in particular an increasing epidemic of multidrug resistant pathogenic microorganisms, as well as a declining proportion of FDA-approved antimicrobial drugs over the past three decades, AMR is now recognised worldwide as one of the greatest threats facing humankind in the 21st century. Antimicrobial peptides and proteins (AMPs) exist widely throughout nature and protect organisms from infection by destroying a broad range of pathogens. Caenopore-5, Snakin-1 and Glycocin F are three representative examples of cysteine-rich antimicrobial proteins which have been synthesized successfully using native chemical ligation (NCL) strategies. Caenopore-5 (Cp-5) is a pore forming AMP expressed in the intestine of the nematode Caenorhabditis elegans. This 82-residue protein was successfully synthesized by NCL of two smaller fragments (35 and 47 amino acids in length) and folded to give the correct protein structure.1Snakin-1 (SN1) is a 63-residue member of the GASA/snakin superfamily proteins isolated from potato tubers. The chemical synthesis of snakin-1 was accomplished by ligation of smaller unprotected polypeptide building blocks that were, in turn, assembled using solid-phase synthesis. The full-length linear peptides were folded using a thiol redox couple at neutral pH.2Glycocin F is a 43-amino acid bacteriocin produced by the gram-positive bacterium Lactobacillus plantarum KW30 and contains two β-linked N-acetylglucosamine (GlcNAc) moieties attached to the sulfur atom of Cys43 and the γ-oxygen of Ser18.3 Due to the unique and non-specific bactericidal mechanism of action of AMPs, it is thus believed that AMPs have a lower tendency to elicit antibiotic resistance than conventional antibiotics, and have hence been recognised as potentially useful therapeutic agents.

  1. (a) Medini, K.; Harris, P. W.; Menorca, A.; Hards, K.; Cook, G. M.; Brimble, M. A., Synthesis and activity of a diselenide bond mimetic of the antimicrobial protein caenopore-5. Chemical Science 2016, 7, 2005-2010. (b) Medini, K.; Harris, P. W.; Hards, K.; Dingley, A. J.; Cook, G. M.; Brimble, M. A., Chemical Synthesis of A Pore‐Forming Antimicrobial Protein, Caenopore‐5, by Using Native Chemical Ligation at a Glu‐Cys Site. ChemBioChem 2015, 16, 328-336.
  2. (a) Yeung, H.; Squire, C. J.; Yosaatmadja, Y.; Panjikar, S.; López, G.; Molina, A.; Baker, E. N.; Harris, P. W.; Brimble, M. A., Radiation Damage and Racemic Protein Crystallography Reveal the Unique Structure of the GASA/Snakin Protein Superfamily. Angewandte Chemie International Edition 2016, 55, 7930-7933; (b) Harris, P. W.; Yang, S. H.; Molina, A.; López, G.; Middleditch, M.; Brimble, M. A., Plant Antimicrobial Peptides Snakin‐1 and Snakin‐2: Chemical Synthesis and Insights into the Disulfide Connectivity. Chemistry–A European Journal 2014, 20, 5102-5110.
  3. Brimble, M. A.; Edwards, P. J.; Harris, P. W.; Norris, G. E.; Patchett, M. L.; Wright, T. H.; Yang, S. H.; Carley, S. E., Synthesis of the Antimicrobial S‐Linked Glycopeptide, Glycocin F. Chemistry–A European Journal 2015, 21, 3556-3561.