Structure of a cyclic indolicidin peptide derivative with higher charge

Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 20 
  • Conformers Submitted: 10 
  • Selection Criteria: structures with the least restraint violations,structures with the lowest energy 

wwPDB Validation   3D Report Full Report

This is version 1.3 of the entry. See complete history


Structure-based design of an indolicidin peptide analogue with increased protease stability

Rozek, A.Powers, J.P.Friedrich, C.L.Hancock, R.E.

(2003) Biochemistry 42: 14130-14138

  • DOI: https://doi.org/10.1021/bi035643g
  • Primary Citation of Related Structures:  
    1QX9, 1QXQ

  • PubMed Abstract: 

    Indolicidin is an antimicrobial cationic peptide with broad-spectrum activity isolated from bovine neutrophils. An indolicidin analogue CP-11, ILKKWPWWPWRRK-NH(2), with improved activity against Gram-negative bacteria had increased positive charge and amphipathicity while maintaining the short length of the parent molecule. The structure of CP-11 in the presence of dodecylphosphocholine (DPC) micelles was determined using nuclear magnetic resonance spectroscopy. CP-11 was found to be an amphipathic molecule with a U-shaped backbone bringing the N- and C-termini in close proximity. On the basis of this close proximity, a cyclic disulfide-bonded peptide cycloCP-11, ICLKKWPWWPWRRCK-NH(2), was designed to stabilize the lipid-bound structure and to increase protease resistance. The three-dimensional structure of cycloCP-11 was determined under the same conditions as for the linear peptide and was found to be similar to CP-11. Both CP-11 and cycloCP-11 associated with phospholipid membranes in a similar manner as indicated by circular dichroism and fluorescence spectra. The minimal inhibitory concentrations of CP-11 and cycloCP-11 for a range of bacteria differed by no more than 2-fold, and they were nonhemolytic at concentrations up to 256 microg/mL. Cyclization was found to greatly increase protease stability. The half-life of cycloCP-11 in the presence of trypsin was increased by 4.5-fold from 4 to 18 min. More importantly, the antibacterial activity of cycloCP-11, but not that of CP-11, in the presence of trypsin was completely retained up to 90 min since the major degradation product was equally active. A structural comparison of CP-11 and cycloCP-11 revealed that the higher trypsin resistance of cycloCP-11 may be due to the more compact packing of lysine and tryptophan side chains. These findings suggest that cyclization may serve as an important strategy in the rational design of antimicrobial peptides.

  • Organizational Affiliation

    Department of Microbiology and Immunology, University of British Columbia, #300-6174 University Boulevard, Vancouver, British Columbia, Canada.


Find similar proteins by:  Sequence   |   3D Structure  

Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Membrane Entity: Yes 
Find proteins for P33046 (Bos taurus)
Explore P33046 
Go to UniProtKB:  P33046
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP33046
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 20 
  • Conformers Submitted: 10 
  • Selection Criteria: structures with the least restraint violations,structures with the lowest energy 

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2003-12-30
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2021-10-27
    Changes: Data collection, Database references, Derived calculations