2M2Q

Solution structure of MCh-1: A novel inhibitor cystine knot peptide from Momordica charantia


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

wwPDB Validation 3D Report Full Report


This is version 1.0 of the entry. See complete history

Literature

Novel Inhibitor Cystine Knot Peptides from Momordica charantia.

He, W.J.Chan, L.Y.Clark, R.J.Tang, J.Zeng, G.Z.Franco, O.L.Cantacessi, C.Craik, D.J.Daly, N.L.Tan, N.H.

(2013) Plos One 8: e75334-e75334

  • DOI: 10.1371/journal.pone.0075334
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • 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 ...

    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.


    Organizational Affiliation

    State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, People's Republic of China.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Inhibitor cystine knot peptide MCh-1
A
32Momordica charantiaMutation(s): 0 
Find proteins for V5IRT8 (Momordica charantia)
Go to UniProtKB:  V5IRT8
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2013-11-06
    Type: Initial release