The chains of the heterodimeric amphibian skin antimicrobial peptide, distinctin, are encoded by separate messenger RNAs

G Evaristo, M Pinkse, Lei Wang, Mei Zhou, Youjia Wu, Hui Wang, Tianbao Chen, Christopher Shaw, P Verhaert

Research output: Contribution to journalArticle

6 Citations (Scopus)
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Abstract

Using a primer to a conserved nucleotide sequence of previously-cloned skin peptides of Phyllomedusa species, two distinct cDNAs were “shotgun” cloned from a skin secretion-derived cDNA library of the frog, Phyllomedusa burmeisteri. The two ORFs separately encode chains A and B of an analog of the previously-reported heterodimeric peptide, distinctin. LC-MS/MS analysis of native versus dithiotreitol reduced crude venom, confirmed the predicted primary sequences as well as the cystine link between the two monomers. Distinctin predominantly exists in the venom as a heterodimer (A-B), neither of the constituent peptides were detected as monomer, whereas of the two possible homodimers (A-A or B-B), only B-B was detected in comparatively low quantity. In vitro dimerization of synthetic replicates of the monomers demonstrated that besides heterodimer, both homodimers are also formed in considerable amounts. Distinctin is the first example of an amphibian skin dimeric peptide that is formed by covalent linkage of two chains that are the products of different mRNAs. How this phenomenon occurs in vivo, to exclude significant homodimer formation, is unclear at present but a “favored steric state” type of interaction between chains is most likely.
Original languageEnglish
Pages (from-to)245-253
Number of pages9
JournalJournal of proteomics
Volume78
DOIs
Publication statusPublished - 14 Jan 2013

Keywords

  • Amphibian skin peptides; cDNA cloning; Heterodimer; Homodimer; Intramolecular and intermolecular disulfide bonds; Peptidomics

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics

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