document: Computing transient gating charge movement of voltage-dependent ion channels The opening of voltage-gated sodium , potassium , and calcium ion channels has a steep relationship with voltage . In response to changes in the transmembrane voltage , structural movements of an ion channel that precede channel opening generate a capacitative gating current . The net gating charge displacement due to membrane depolarization is an index of the voltage sensitivity of the ion channel activation process . Understanding the molecular basis of voltage-dependent gating of ion channels requires the measurement and computation of the gating charge , Q . We derive a simple and accurate semianalytic approach to computing the voltage dependence of transient gating charge movement -LRB- Q-V relationship -RRB- of discrete Markov state models of ion channels using matrix methods . This approach allows rapid computation of Q-V curves for finite and infinite length step depolarizations and is consistent with experimentally measured transient gating charge . This computational approach was applied to Shaker potassium channel gating , including the impact of inactivating particles on potassium channel gating currents
doc_bio_tags: O B I I I O O B I O O O O O O O O O O B I O O O O O O O O O O O O O B I O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O B I I I O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O
extractive_keyphrases: transient gating charge movement transmembrane voltage gating current ion channels
abstractive_keyphrases: action potentials charge movement inactivation immobilization markov state model