Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 4.55 kDa 
• Atom Count: 348 
• Modelled Residue Count: 35 
• Deposited Residue Count: 35 
• Unique protein chains: 1

 4Z7P

X-ray structure of racemic ShK Q16K toxin

• PDB DOI:  https://doi.org/10.2210/pdb4Z7P/pdb

• Classification: TOXIN
• Organism(s): Stichodactyla helianthus
• Mutation(s): Yes 


• Deposited: 2015-04-07 Released: 2015-09-09 
• Deposition Author(s): Sickmier, E.A.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.20 Å
• R-Value Free: 0.227 
• R-Value Work: 0.204 
• R-Value Observed: 0.205 

Literature

Pharmaceutical Optimization of Peptide Toxins for Ion Channel Targets: Potent, Selective, and Long-Lived Antagonists of Kv1.3.

Murray, J.K., Qian, Y.X., Liu, B., Elliott, R., Aral, J., Park, C., Zhang, X., Stenkilsson, M., Salyers, K., Rose, M., Li, H., Yu, S., Andrews, K.L., Colombero, A., Werner, J., Gaida, K., Sickmier, E.A., Miu, P., Itano, A., McGivern, J., Gegg, C.V., Sullivan, J.K., Miranda, L.P.

(2015) J Med Chem 58: 6784-6802

• PubMed: 26288216 
• DOI: https://doi.org/10.1021/acs.jmedchem.5b00495
• Primary Citation of Related Structures:  
  4Z7P


• PubMed Abstract: 
  

To realize the medicinal potential of peptide toxins, naturally occurring disulfide-rich peptides, as ion channel antagonists, more efficient pharmaceutical optimization technologies must be developed. Here, we show that the therapeutic properties of multiple cysteine toxin peptides can be rapidly and substantially improved by combining direct chemical strategies with high-throughput electrophysiology. We applied whole-molecule, brute-force, structure-activity analoging to ShK, a peptide toxin from the sea anemone Stichodactyla helianthus that inhibits the voltage-gated potassium ion channel Kv1.3, to effectively discover critical structural changes for 15× selectivity against the closely related neuronal ion channel Kv1.1. Subsequent site-specific polymer conjugation resulted in an exquisitely selective Kv1.3 antagonist (>1000× over Kv1.1) with picomolar functional activity in whole blood and a pharmacokinetic profile suitable for weekly administration in primates. The pharmacological potential of the optimized toxin peptide was demonstrated by potent and sustained inhibition of cytokine secretion from T cells, a therapeutic target for autoimmune diseases, in cynomolgus monkeys.

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Organizational Affiliation: 

Therapeutic Discovery, Amgen Inc. , 360 Binney Street, Cambridge, Massachusetts 02142, United States.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Potassium channel toxin kappa-stichotoxin-She1a	A	35	Stichodactyla helianthus	Mutation(s): 1
UniProt
Find proteins for P29187 (Stichodactyla helianthus) Explore P29187  Go to UniProtKB:  P29187

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
SO4	B [auth A], C [auth A], D [auth A], E [auth A], F [auth A]	SULFATE ION O4 S QAOWNCQODCNURD-UHFFFAOYSA-L

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.20 Å
• R-Value Free: 0.227 
• R-Value Work: 0.204 
• R-Value Observed: 0.205 
• Space Group: H -3

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 60.783	α = 90
b = 60.783	β = 90
c = 43.592	γ = 120

Software Package:

Software Name	Purpose
SCALEPACK	data scaling
PHASER	phasing
REFMAC	refinement
PDB_EXTRACT	data extraction
HKL-2000	data reduction

Structure Validation

Entry History 

Deposition Data

• Released Date: 2015-09-09 
Deposition Author(s): Sickmier, E.A.

Revision History  

• Version 1.0: 2015-09-09
  Type: Initial release
  
• Version 1.1: 2015-09-23
  Changes: Database references