2KNI

High-resolution solution structure of the ASIC1a blocker PcTX1


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 300 
  • Conformers Submitted: 25 
  • Selection Criteria: Best MolProbity score 

wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

A dynamic pharmacophore drives the interaction between Psalmotoxin-1 and the putative drug target acid-sensing ion channel 1a.

Saez, N.J.Mobli, M.Bieri, M.Chassagnon, I.R.Malde, A.K.Gamsjaeger, R.Mark, A.E.Gooley, P.R.Rash, L.D.King, G.F.

(2011) Mol Pharmacol 80: 796-808

  • DOI: 10.1124/mol.111.072207
  • Primary Citation of Related Structures:  
    2KNI

  • PubMed Abstract: 
  • Acid-sensing ion channel 1a (ASIC1a) is a primary acid sensor in the peripheral and central nervous system. It has been implicated as a novel therapeutic target for a broad range of pathophysiological conditions including pain, ischemic stroke, depression, and autoimmune diseases such as multiple sclerosis ...

    Acid-sensing ion channel 1a (ASIC1a) is a primary acid sensor in the peripheral and central nervous system. It has been implicated as a novel therapeutic target for a broad range of pathophysiological conditions including pain, ischemic stroke, depression, and autoimmune diseases such as multiple sclerosis. The only known selective blocker of ASIC1a is π-TRTX-Pc1a (PcTx1), a disulfide-rich 40-residue peptide isolated from spider venom. π-TRTX-Pc1a is an effective analgesic in rodent models of acute pain and it provides neuroprotection in a mouse model of ischemic stroke. Thus, understanding the molecular basis of the π-TRTX-Pc1a-ASIC1a interaction should facilitate development of therapeutically useful ASIC1a blockers. We therefore developed an efficient bacterial expression system to produce a panel of π-TRTX-Pc1a mutants for probing structure-activity relationships as well as isotopically labeled toxin for determination of its solution structure and dynamics. We demonstrate that the toxin pharmacophore resides in a β-hairpin loop that was revealed to be mobile over a wide range of time scales using molecular dynamics simulations in combination with NMR spin relaxation and relaxation dispersion measurements. The toxin-receptor interaction was modeled by in silico docking of the toxin structure onto a homology model of rat ASIC1a in a restraints-driven approach that was designed to take account of the dynamics of the toxin pharmacophore and the consequent remodeling of side-chain conformations upon receptor binding. The resulting model reveals new insights into the mechanism of action of π-TRTX-Pc1a and provides an experimentally validated template for the rational design of therapeutically useful π-TRTX-Pc1a mimetics.


    Related Citations: 
    • Recombinant production and solution structure of PcTx1, the specific peptide inhibitor of ASIC1a proton-gated cation channels.
      Escoubas, P., Bernard, C., Lambeau, G., Lazdunski, M., Darbon, H.
      (2003) Protein Sci 12: 1332

    Organizational Affiliation

    Institute for Molecular Bioscience, University of Queensland, 306 Carmody Road, St Lucia, QLD 4072, Australia.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Psalmotoxin-1A41Psalmopoeus cambridgeiMutation(s): 0 
UniProt
Find proteins for P60514 (Psalmopoeus cambridgei)
Explore P60514 
Go to UniProtKB:  P60514
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 300 
  • Conformers Submitted: 25 
  • Selection Criteria: Best MolProbity score 
  • OLDERADO: 2KNI Olderado

Structure Validation

View Full Validation Report




Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2010-09-01
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2013-01-30
    Changes: Database references
  • Version 1.3: 2020-02-26
    Changes: Data collection, Database references, Other