title: A new family of cystine knot peptides from the seeds of Momordica cochinchinensis.
abstract: Momordica cochinchinensis, a Cucurbitaceae plant commonly found in Southeast Asia, has the unusual property of containing both acyclic and backbone-cyclized trypsin inhibitors with inhibitor cystine knot (ICK) motifs. In the current study we have shown that M. cochinchinensis also contains another family of acyclic ICK peptides. We recently reported two novel peptides from M. cochinchinensis but have now discovered four additional peptides (MCo-3-MCo-6) with related sequences. Together these peptides form a novel family of M. cochinchinensis ICK peptides (MCo-ICK) that do not have sequence homology with other known peptides and are not potent trypsin inhibitors. Otherwise these new peptides MCo-3 to MCo-6 were evaluated for antimalarial activity against Plasmodium falciparum, and cytotoxic activity against the cancer cell line MDA-MB-231. But these peptides were not active.
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia.
authors.forename: Lai Yue
authors.initials: LY
authors.lastname: Chan
authors.forename: Wenjun
authors.initials: W
authors.lastname: He
authors.forename: Ninghua
authors.initials: N
authors.lastname: Tan
authors.forename: Guangzhi
authors.initials: G
authors.lastname: Zeng
authors.forename: David J
authors.initials: DJ
authors.lastname: Craik
authors.forename: Norelle L
authors.initials: NL
authors.lastname: Daly
mesh_terms: D000595:Amino Acid Sequence; D000962:Antimalarials / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D045744:Cell Line, Tumor; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D008969:Molecular Sequence Data; D008970:Molecular Weight; D029775:Momordica / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D010940:Plant Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D010963:Plasmodium falciparum / Q000187:drug effects; D012639:Seeds / Q000737:chemistry*; D020539:Sequence Analysis, Protein; D053719:Tandem Mass Spectrometry
chemical_list: D000962:Antimalarials; D000972:Antineoplastic Agents, Phytogenic; D010455:Peptides; D010936:Plant Extracts; D010940:Plant Proteins