Biological Assembly 1  

 3D View: Structure

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 5-mer - A4B1 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 71.18 kDa 
• Atom Count: 3179 
• Modelled Residue Count: 425 
• Deposited Residue Count: 657 
• Unique protein chains: 2

2A9H

NMR structural studies of a potassium channel / charybdotoxin complex

• DOI: 10.2210/pdb2A9H/pdb
• BMRB: 6728

• Classification: METAL TRANSPORT, membrane protein
• Organism(s): Streptomyces lividans
• Expression System: Escherichia coli
• Mutation(s): Yes 


• Deposited: 2005-07-11 Released: 2006-01-10 
• Deposition Author(s): Yu, L., Sun, C., Song, D., Shen, J., Xu, N., Gunasekera, A., Hajduk, P.J., Olejniczak, E.T.

---

Experimental Data Snapshot

• Method: SOLUTION NMR
• Conformers Submitted: 1 

Literature

Nuclear magnetic resonance structural studies of a potassium channel-charybdotoxin complex.

Yu, L., Sun, C., Song, D., Shen, J., Xu, N., Gunasekera, A., Hajduk, P.J., Olejniczak, E.T.

(2005) Biochemistry 44: 15834-15841

• PubMed: 16313186 
• DOI: 10.1021/bi051656d
• Primary Citation of Related Structures:  
  2A9H


• PubMed Abstract: 
  

Ion channels play critical roles in signaling processes and are attractive targets for treating various diseases. Here we describe an NMR-based strategy for structural analyses of potassium channel-ligand complexes using KcsA (residues 1-132, with six mutations to impart toxin binding and to mimic the eukaryotic hERG channel). Using this approach, we determined the solution structure of KcsA in complex with the high-affinity peptide antagonist charybdotoxin. The structural data reveal how charybdotoxin binds to the closed form of KcsA and makes specific contacts with the extracellular surface of the ion channel, resulting in pore blockage. This represents the first direct structural information about an ion channel complexed to a peptide antagonist and provides an experimental framework for understanding and interpreting earlier mutational analyses. The strategy presented here overcomes many of the limitations of conventional NMR approaches to helical membrane protein structure determination and can be applied in the study of the binding of druglike molecules to this important class of proteins.

---

Organizational Affiliation: 

Pharmaceutical Discovery Division, GPRD, Abbott Laboratories, Abbott Park, Illinois 60064-6098, USA.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Voltage-gated potassium channel	A, B, C, D	155	Streptomyces lividans	Mutation(s): 7  Gene Names: kcsA, skc1
Find proteins for P0A334 (Streptomyces lividans) Explore P0A334  Go to UniProtKB:  P0A334

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
charybdotoxin	E	37	N/A	Mutation(s): 0
Find proteins for P13487 (Leiurus hebraeus) Explore P13487  Go to UniProtKB:  P13487

Small Molecules

Modified Residues  1 Unique
ID	Chains	Type	Formula	2D Diagram	Parent
PCA	E	L-PEPTIDE LINKING	C5 H7 N O3		GLN

Experimental Data & Validation

Experimental Data

• Method: SOLUTION NMR
• Conformers Submitted: 1 
• OLDERADO: 2A9H Olderado

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2005-07-11 
• Released Date: 2006-01-10 
Deposition Author(s): Yu, L., Sun, C., Song, D., Shen, J., Xu, N., Gunasekera, A., Hajduk, P.J., Olejniczak, E.T.

Revision History  

• Version 1.0: 2006-01-10
  Type: Initial release
  
• Version 1.1: 2008-04-30
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance
• Version 2.0: 2019-12-25
  Changes: Database references, Derived calculations, Polymer sequence