TY - JOUR
T1 - Engineering a stable and selective peptide blocker of the Kv1.3 channel in T lymphocytes
AU - Pennington, Michael W
AU - Beeton, Christine
AU - Galea, Charles
AU - Smith, Brian J
AU - Chi, Victor
AU - Monaghan, Kevin P
AU - Garcia, Adriana
AU - Rangaraju, Srikant
AU - Giuffrida, Alfred
AU - Plank, Denise K
AU - Crossley, Geroge
AU - Nugent, Daniel
AU - Khaytin, Ilya
AU - LeFievre, Yann
AU - Peshenko, Irina
AU - Dixon, Catherine
AU - Chauhan, Satendra
AU - Orzel, Alicia
AU - Inoue, Taeko
AU - Hu, Xueyou
AU - Moore, Rebecca V
AU - Norton, Raymond Stanley
AU - Chandy, K George
PY - 2009
Y1 - 2009
N2 - 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 me- thionine 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 ?g/kg, 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 ?g/kg by subcutaneous injection once daily. ShK-192 has potential as a therapeutic for autoimmune diseases mediated by T EM cells
AB - 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 me- thionine 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 ?g/kg, 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 ?g/kg by subcutaneous injection once daily. ShK-192 has potential as a therapeutic for autoimmune diseases mediated by T EM cells
UR - http://molpharm.aspetjournals.org/content/75/4/762
U2 - 10.1124/mol.108.052704
DO - 10.1124/mol.108.052704
M3 - Article
SN - 0026-895X
VL - 75
SP - 762
EP - 773
JO - Molecular Pharmacology
JF - Molecular Pharmacology
IS - 4
ER -