2m2r

Solution structure of MCh-2: A novel inhibitor cystine knot peptide from Momordica charantia

spinqualitylabelsall models 2m2r Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2m2r is a 1 chain structure with sequence from Momordica charantia. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Solution NMR, 20 models Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Two new peptides, MCh-1 and MCh-2, along with three known trypsin inhibitors (MCTI-I, MCTI-II and MCTI-III), were isolated from the seeds of the tropical vine Momordica charantia. The sequences of the peptides were determined using mass spectrometry and NMR spectroscopy. Using a strategy involving partial reduction and stepwise alkylation of the peptides, followed by enzymatic digestion and tandem mass spectrometry sequencing, the disulfide connectivity of MCh-1 was elucidated to be CysI-CysIV, CysII-CysV and CysIII-CysVI. The three-dimensional structures of MCh-1 and MCh-2 were determined using NMR spectroscopy and found to contain the inhibitor cystine knot (ICK) motif. The sequences of the novel peptides differ significantly from peptides previously isolated from this plant. Therefore, this study expands the known peptide diversity in M. charantia and the range of sequences that can be accommodated by the ICK motif. Furthermore, we show that a stable two-disulfide intermediate is involved in the oxidative folding of MCh-1. This disulfide intermediate is structurally homologous to the proposed ancestral fold of ICK peptides, and provides a possible pathway for the evolution of this structural motif, which is highly prevalent in nature. Novel Inhibitor Cystine Knot Peptides from Momordica charantia.,He WJ, Chan LY, Clark RJ, Tang J, Zeng GZ, Franco OL, Cantacessi C, Craik DJ, Daly NL, Tan NH PLoS One. 2013 Oct 8;8(10):e75334. doi: 10.1371/journal.pone.0075334. PMID:24116036 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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