Crystals
  • Featured Post

    2014 is the international year of crystallography. Therefore, I thought I would celebrate by sharing some interesting links and videos about X-ray crystallography, which is a subject that is very close to my heart.

    This picture is of some of my own protein crystals that I grew as a graduate student. Watch my thesis defence lecture which can be found on the 'My Work' page to learn more about them.

Check it out.

The Spark of Life – Book Review

I had the great pleasure in late October to attend the awarding of the Lewis Thomas Prize for Writing about Science to Dr Frances Ashcroft for her book The Spark of Life. The ceremony included a lecture by the author followed by a dinner at the Rockefeller University President’s  house and further discussion with the … Continue reading

Proton Channel Speakers

Proton Channels at the Biophysical Society Meeting – 2013

This year was a big year for Hv at the Biophysical Society meeting in Philidephia (Feb. 2-6th). With a symposium and a platform session dedicated to Hv related talks, the meeting boasted a large contingent of scientists studying this channel. I was in attendance and really enjoyed meeting all my fellow Hv researchers whose work I have … Continue reading

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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

Journal Club: Tracking a complete voltage-sensor cycle with metal-ion bridges

In this post I would like to start an online discussion about a very interesting recent PNAS paper: Tracking a complete voltage-sensor cycle with metal-ion bridges by Henrion et al. I know that other people in the voltage-gated cation channel field are very interested in this paper and it also relates to many of the … Continue reading

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Omega Current Channelopathies

In this post I will be continuing my series on the omega current. The omega current is a leak current that passes through the voltage-sensor domain (VSD) of mutated voltage-gated cation channels. Mutation of the VSD S4 helix can reveal a cryptic pore that allows ions (H+, Li+, K+, Rb+ and even guanidinium) to cross … Continue reading

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The Omega Current

Mutation of voltage-sensor domains (VSDs) can sometimes lead to ions leaking across the membrane through the VSDs themselves. Ion conduction through the mutated VSD of the Shaker Kv channel was coined the “omega current” by Tombola, Pathak and Isacoff (Tombola et al., 2005). Many different mutations have been identified that result in current leaking through the VSDs of … Continue reading

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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

Breast cancer cell featured image

Hv Physiology: Breast Cancer

In this post I will discuss the role of human Hv1 channels in promoting the pathology and invasiveness of breast cancers. It is well known that cancer consists of normal cells gone awry. As cells age, they can accumulate mutations in their genomes and sometimes these mutations lead to unregulated growth and expansion. The unregulated, … Continue reading

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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

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Human Hv1: Architectural Overview

Although voltage-gated proton currents have been measured in cell membranes since the early 1980s (Tomas & Meech, 1982), the genes encoding the voltage-gated proton channels were not discovered until 2006 (Sasaki et al., 2006; Ramsey et al., 2006). What the gene sequence demonstrated was that Hv channels share sequence homology with the voltage-sensor domains (VSDs) of … Continue reading

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