2K9E

NMR Solution Structure for ShK-192: A Potent KV1.3-Specific Immunosuppressive Polypeptide

Summary for 2K9E

• Entry DOI: 10.2210/pdb2k9e/pdb
• NMR Information: BMRB: 15983
• Descriptor: Kappa-stichotoxin-She3a (1 entity in total)
• Functional Keywords: protein, ionic channel inhibitor, nematocyst, neurotoxin, potassium channel inhibitor, secreted, toxin
• Biological source: Stichodactyla helianthus
• Total number of polymer chains: 1
• Total formula weight: 4422.17

Authors

Galea, C.A. (deposition date: 2008-10-09, release date: 2009-01-20, Last modification date: 2023-11-15)

Primary citation

Pennington, M.W.,Beeton, C.,Galea, C.A.,Smith, B.J.,Chi, V.,Monaghan, K.P.,Garcia, A.,Rangaraju, S.,Giuffrida, A.,Plank, D.,Crossley, G.,Nugent, D.,Khaytin, I.,Lefievre, Y.,Peshenko, I.,Dixon, C.,Chauhan, S.,Orzel, A.,Inoue, T.,Hu, X.,Moore, R.V.,Norton, R.S.,Chandy, K.G.
Engineering a stable and selective peptide blocker of the Kv1.3 channel in T lymphocytes
Mol.Pharmacol., 75:762-773, 2009

PubMed Abstract: Kv1.3 potassium channels maintain the membrane potential of effector memory (T(EM)) T cells that are important mediators of multiple sclerosis, type 1 diabetes mellitus, and rheumatoid arthritis. The polypeptide ShK-170 (ShK-L5), containing an N-terminal phosphotyrosine extension of the Stichodactyla helianthus ShK toxin, is a potent and selective blocker of these channels. However, a stability study of ShK-170 showed minor pH-related hydrolysis and oxidation byproducts that were exacerbated by increasing temperatures. We therefore engineered a series of analogs to minimize the formation of these byproducts. The analog with the greatest stability, ShK-192, contains a nonhydrolyzable phosphotyrosine surrogate, a methionine isostere, and a C-terminal amide. ShK-192 shows the same overall fold as ShK, and there is no evidence of any interaction between the N-terminal adduct and the rest of the peptide. The docking configuration of ShK-192 in Kv1.3 shows the N-terminal para-phosphonophenylalanine group lying at the junction of two channel monomers to form a salt bridge with Lys(411) of the channel. ShK-192 blocks Kv1.3 with an IC(50) of 140 pM and exhibits greater than 100-fold selectivity over closely related channels. After a single subcutaneous injection of 100 microg/kg, approximately 100 to 200 pM concentrations of active peptide is detectable in the blood of Lewis rats 24, 48, and 72 h after the injection. ShK-192 effectively inhibits the proliferation of T(EM) cells and suppresses delayed type hypersensitivity when administered at 10 or 100 microg/kg by subcutaneous injection once daily. ShK-192 has potential as a therapeutic for autoimmune diseases mediated by T(EM) cells.

PubMed: 19122005
DOI: 10.1124/mol.108.052704

Experimental method

SOLUTION NMR