title: The chains of the heterodimeric amphibian skin antimicrobial peptide, distinctin, are encoded by separate messenger RNAs.
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.
authors.affiliation: Analytical Biotechnology Group and Netherlands Proteomics Centre, Department of Biotechnology, Delft University of Technology, Delft, the Netherlands.
authors.forename: Geisa
authors.initials: G
authors.lastname: Evaristo
authors.forename: Martijn
authors.initials: M
authors.lastname: Pinkse
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Mei
authors.initials: M
authors.lastname: Zhou
authors.forename: Youjia
authors.initials: Y
authors.lastname: Wu
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Tianbao
authors.initials: T
authors.lastname: Chen
authors.forename: Chris
authors.initials: C
authors.lastname: Shaw
authors.forename: Peter
authors.initials: P
authors.lastname: Verhaert
mesh_terms: D029845:Amphibian Proteins / Q000096:biosynthesis* / Q000235:genetics; D000664:Amphibian Venoms / Q000378:metabolism*; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000096:biosynthesis* / Q000235:genetics; D001001:Anura / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D015723:Gene Library; D016366:Open Reading Frames / Q000502:physiology; D055503:Protein Multimerization / Q000502:physiology; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics; D012867:Skin / Q000378:metabolism*
chemical_list: D029845:Amphibian Proteins; D000664:Amphibian Venoms; D023181:Antimicrobial Cationic Peptides; D012333:RNA, Messenger; C531945:distinctin