title: Plant antimicrobial peptides snakin-1 and snakin-2: chemical synthesis and insights into the disulfide connectivity.
abstract: Antimicrobial peptides and proteins represent an important class of plant defensive compounds against pathogens and provide a rich source of lead compounds in the field of drug discovery. We describe the effective preparation of the cysteine-rich snakin-1 and -2 antimicrobial peptides by using a combination of solid-phase synthesis and native chemical ligation. A subsequent cysteine/cystine mediated oxidative folding to form the six internal disulfide bonds concurrently gave the folded proteins in 40-50 % yield. By comparative evaluation of mass spectrometry, HPLC, biological data and trypsin digest mapping of folded synthetic snakin-2 compared to natural snakin-2, we demonstrated that synthetic snakin-2 possesses full antifungal activity and displayed similar chromatographic behaviour to natural snakin-2. Trypsin digest analysis allowed tentative assignment of three of the purported six disulfide bonds.
authors.affiliation: School of Chemical Sciences, The University of Auckland, 23 Symonds St., Auckland 1142 (New Zealand), Fax: (+64) 93737422; Maurice Wilkins Centre for Molecular Biodiscovery, School of Biological Sciences, The University of Auckland, Auckland 1142 (New Zealand). paul.harris@auckland.ac.nz.
authors.forename: Paul W R
authors.initials: PW
authors.lastname: Harris
authors.forename: Sung-Hyun
authors.initials: SH
authors.lastname: Yang
authors.forename: Antonio
authors.initials: A
authors.lastname: Molina
authors.forename: Gemma
authors.initials: G
authors.lastname: López
authors.forename: Martin
authors.initials: M
authors.lastname: Middleditch
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Brimble
mesh_terms: D000595:Amino Acid Sequence; D000890:Anti-Infective Agents / Q000138:chemical synthesis* / Q000737:chemistry; D001688:Biological Products / Q000138:chemical synthesis* / Q000737:chemistry; D003545:Cysteine / Q000737:chemistry; D003553:Cystine / Q000737:chemistry; D004220:Disulfides / Q000737:chemistry; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis* / Q000737:chemistry; D010940:Plant Proteins / Q000138:chemical synthesis* / Q000737:chemistry; D017510:Protein Folding; D011198:Solanum tuberosum / Q000737:chemistry*; D060327:Solid-Phase Synthesis Techniques
chemical_list: D000890:Anti-Infective Agents; D001688:Biological Products; D004220:Disulfides; D010455:Peptides; D010940:Plant Proteins; C117071:SN1 protein, Solanum tuberosum; D003553:Cystine; D003545:Cysteine
keywords: antibiotics; natural products; peptides; solid-phase synthesis; structural biology