1RKK

POLYPHEMUSIN I NMR SOLUTION STRUCTURE


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 17 
  • Selection Criteria: structures with the lowest energy 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structure-activity relationships for the beta-hairpin cationic antimicrobial peptide polyphemusin I.

Powers, J.P.S.Rozek, A.Hancock, R.E.W.

(2004) BIOCHIM.BIOPHYS.ACTA 1698: 239-250

  • DOI: 10.1016/j.bbapap.2003.12.009

  • PubMed Abstract: 
  • The solution structure of polyphemusin I was determined using (1)H-NMR spectroscopy. Polyphemusin I was found to be an amphipathic, beta-hairpin connected by a type I' beta-turn. The 17 low-energy structures aligned very well over the beta-sheet regi ...

    The solution structure of polyphemusin I was determined using (1)H-NMR spectroscopy. Polyphemusin I was found to be an amphipathic, beta-hairpin connected by a type I' beta-turn. The 17 low-energy structures aligned very well over the beta-sheet region while both termini were poorly defined due in part to a hinge-like region centred in the molecule about arginine residues 6 and 16. Conversely, a linear analogue, PM1-S, with all cysteines simultaneously replaced with serine was found to be dynamic in nature, and a lack of medium and long-range NOEs indicated that this molecule displayed no favoured conformation. Circular dichroism (CD) spectroscopy confirmed that in solution, 50% trifluoroethanol (TFE) and in the presence of liposomes, PM1-S remained unstructured. The antimicrobial activity of PM1-S was found to be 4- to 16-fold less than that of polyphemusin I and corresponded with a 4-fold reduction in bacterial membrane depolarization. Both peptides were able to associate with lipid bilayers in a similar fashion; however, PM1-S was completely unable to translocate model membranes while polyphemusin I retained this activity. It was concluded that the disulfide-constrained, beta-sheet structure of polyphemusin I is required for maximum antimicrobial activity. Disruption of this structure results in reduced antimicrobial activity and completely abolishes membrane translocation indicating that the linear PM1-S acts through a different antimicrobial mechanism.


    Organizational Affiliation

    Department of Microbiology and Immunology, University of British Columbia, #300-6174 University Boulevard, Vancouver, British Columbia, V6T 1Z3, Canada.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
POLYPHEMUSIN I
A
19Limulus polyphemusMutation(s): 0 
Find proteins for P14215 (Limulus polyphemus)
Go to UniProtKB:  P14215
Small Molecules
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
NH2
Query on NH2
A
NON-POLYMERH2 N

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Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 17 
  • Selection Criteria: structures with the lowest energy 
  • Olderado: 1RKK Olderado

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2004-08-31
    Type: Initial release
  • Version 1.1: 2008-04-29
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance