The importance of charge compensation in the membrane

In this post I continue my series on the omega current by discussing how a mutation that removes a charged group from the voltage-sensor domain (VSD) would be highly destabilizing and disruptive. The omega current is a leak current that passes through the VSD of mutated voltage-gated cation channels. In some cases, the mutated channels … Continue reading

Pores and Selectivity Filters

In this post I will be briefly introducing the classical ideas of ion conduction through membrane proteins. The idea of ion channels as selective pores in the cell membrane is very old but is now understood at atomic detail. So what is a channel? What does an ion conductive pore look like? Here, I will … Continue reading

Biochemical Data Constraining the S4 of Hv

In this post I will finish my series on alignments and homology models. Here, I will discuss three different biochemical studies of the voltage-gated proton channel (Hv) that help to delineate the boundaries of the S4 helix. First, I will discuss the structure of the coiled-coil, which limits where along the primary the sequence of … Continue reading

Is the S4 helix of Hv Short?

In this post, I will elaborate upon a statement I made in last week’s post. There, I discussed how important a proper alignment of the S4 helices in voltage sensor domains (VSDs) is for building accurate homology-based structural models of these domains. ¬†When discussing the potential alignments I stated that “since the different conformations of … Continue reading

The Mechanism of Voltage Gating in Potassium Channels? – Part 2 Activation

OK, time for part 2. If you missed part 1 of this two post series check it out here. Just to recap, I am discussing the recent Science paper (April 13th issue) from the D.E. Shaw Research group, entitled “The Mechanism of Voltage Gating in Potassium Channels.” In this paper, Jensen et al. use their … Continue reading