TY - JOUR
T1 - A potent and selective peptide blocker of the Kv1.3 channel: Prediction from free-energy simulations and experimental confirmation
AU - Rashid, M Harunur
AU - Heinzelmann, Germano
AU - Huq, Redwan
AU - Tajhya, Rajeev B
AU - Chang, Shihchieh Jeff
AU - Chhabra, Sandeep
AU - Pennington, Michael W
AU - Beeton, Christine
AU - Norton, Raymond Stanley
AU - Kuyucak, Serdar
PY - 2013
Y1 - 2013
N2 - The voltage-gated potassium channel Kv1.3 is a well-established target for treatment of autoimmune diseases. ShK peptide from a sea anemone is one of the most potent blockers of Kv1.3 but its application as a therapeutic agent for autoimmune diseases is limited by its lack of selectivity against other Kv channels, in particular Kv1.1. Accurate models of Kv1.x-ShK complexes suggest that specific charge mutations on ShK could considerably enhance its specificity for Kv1.3. Here we evaluate the K18A mutation on ShK, and calculate the change in binding free energy associated with this mutation using the path-independent free energy perturbation and thermodynamic integration methods, with a novel implementation that avoids convergence problems. To check the accuracy of the results, the binding free energy differences were also determined from path-dependent potential of mean force calculations. The two methods yield consistent results for the K18A mutation in ShK and predict a 2 kcal/mol gain in Kv1.3/Kv1.1 selectivity free energy relative to wild-type peptide. Functional assays confirm the predicted selectivity gain for ShK[K18A] and suggest that it will be a valuable lead in the development of therapeutics for autoimmune diseases
AB - The voltage-gated potassium channel Kv1.3 is a well-established target for treatment of autoimmune diseases. ShK peptide from a sea anemone is one of the most potent blockers of Kv1.3 but its application as a therapeutic agent for autoimmune diseases is limited by its lack of selectivity against other Kv channels, in particular Kv1.1. Accurate models of Kv1.x-ShK complexes suggest that specific charge mutations on ShK could considerably enhance its specificity for Kv1.3. Here we evaluate the K18A mutation on ShK, and calculate the change in binding free energy associated with this mutation using the path-independent free energy perturbation and thermodynamic integration methods, with a novel implementation that avoids convergence problems. To check the accuracy of the results, the binding free energy differences were also determined from path-dependent potential of mean force calculations. The two methods yield consistent results for the K18A mutation in ShK and predict a 2 kcal/mol gain in Kv1.3/Kv1.1 selectivity free energy relative to wild-type peptide. Functional assays confirm the predicted selectivity gain for ShK[K18A] and suggest that it will be a valuable lead in the development of therapeutics for autoimmune diseases
UR - http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3820677/pdf/pone.0078712.pdf
U2 - 10.1371/journal.pone.0078712
DO - 10.1371/journal.pone.0078712
M3 - Article
SN - 1932-6203
VL - 8
JO - PLoS ONE
JF - PLoS ONE
IS - 11
M1 - e78712
ER -