Electric field-induced changes in membrane proteins charge movement currents

Our previous study showed that thermal effects induced by Joule heating did not play the pivotal role in damage of membrane proteins when cell membranes were shocked by a pulsed membrane potential up to 500 mV. Our analytical study of ion channel currents further indicated that a brief electric shock may cause protein conformational damage in the channel gating system, resulting in a reduction in the number of limiting gating charge particles. In this paper, we present the results of our study into electric shock-induced changes in the intramembrane charge movement currents. We found that a brief electric shock may significantly alter the characteristics of the charge movement currents of the membrane proteins, including reducing the magnitudes of two components Q(beta) and Q(gamma) broadening the hump shape of Q(gamma) and increasing its time delay. This study suggests that a brief intensive electric shock may cause proteins to structurally alter, reducing the amount of movable charge particles and therefore decreasing the protein functions. These results indicate that electro-coupled structural damage in membrane proteins is an important mechanism involved in electrical injury, especially in a field range not sufficient to cause thermal damage. (c) 2006 Elsevier Ltd and ISBI. All rights reserved.