New perspectives on ion selectivity

Apr 25, 2011
(Left) K+ ion (magenta sphere) is shown bound in the S2 site of the selectivity filter (green ribbon). The backbone carbonyl groups of the S2 site are shown as spheres. (Right) View looking down the pore axis. Atoms are shown in space-filling format. Credit: Dixit, P.D., and D. Asthagiri. 2011. J. Gen. Physiol. doi:10.1085/jgp.201010533.

The latest Perspectives in General Physiology series examines the ion selectivity of cation-selective channels and transporters. The series appears in the May 2011 issue of the Journal of General Physiology.

According to Perspectives Editor Olaf Andersen in his introduction, a key tool in most recent studies on ion selectivity has been the so-called "toy models," which emphasize the fluid-like features of the selectivity filter and allow for the isolation of key features. Although proteins may indeed be fluid-like at small-length scales, however, they show considerable rigidity at longer-length scales. Thus, while toy models allow for important new insights, the goal is to transfer this knowledge into understanding the selectivity of the bilayer-spanning channels. This remains a challenge as it becomes necessary to consider not only the equilibrium situations but also the kinetics, and the competition among the permeant as they strive to make it through the channel.

As demonstrated by the Perspectives contributors in this issue, the questions surrounding ion selectivity can be approached from different, complementary directions. Alam and Jiang focus on what can be deduced from crystal structures; Nimigean and Allen consider what can be learned from a combined electrophysiological, crystallographic, and computational approach; and the last three contributors—Roux et al., Dixit and Asthagiri, and Varma et al. (appearing in the June 2011 issue of the JGP)—consider different theoretical and computational approaches based on MD simulations and quasi-chemical theory, including the use of simple "toy" models, to identify the mechanisms underlying ion selectivity.

Explore further: US scientists make embryonic stem cells from adult skin

More information: Andersen, O.S. 2011. J. Gen. Physiol. doi:10.1085/jgp.201110651
Alam, A., and Y. Jiang. 2011. J. Gen. Physiol. doi:10.1085/jgp.201010546
Nimigean, C.M., and T.W. Allen. 2011. J. Gen. Physiol. doi:10.1085/jgp.201010551
Roux, B., et al. 2011. J. Gen. Physiol. doi:10.1085/jgp.201010577
Dixit, P.D., and D. Asthagiri. 2011. J. Gen. Physiol. doi:10.1085/jgp.201010533

add to favorites email to friend print save as pdf

Related Stories

Gates open on understanding potassium channel controls

Jun 03, 2010

Walter and Eliza Hall Institute scientists have made a significant advance in understanding how potassium channels, which permit the flow of electric currents central to many of the body's biological processes, ...

New perspectives on local calcium signaling

Jul 26, 2010

The latest Perspectives in General Physiology series introduces the newest technologies in the field of calcium signaling, which plays a central role in many cellular processes. The Perspectives appear in ...

Unraveling the mysteries of poison

Apr 13, 2006

Researchers from the Max Planck Institite for Biophysical Chemistry and other German and French colleagues have combined magnetic resonance spectroscopy (solid-state NMR) with special protein synthesis procedures to uncover ...

Recommended for you

Leeches help save woman's ear after pit bull mauling

Apr 18, 2014

(HealthDay)—A pit bull attack in July 2013 left a 19-year-old woman with her left ear ripped from her head, leaving an open wound. After preserving the ear, the surgical team started with a reconnection ...

New pain relief targets discovered

Apr 17, 2014

Scientists have identified new pain relief targets that could be used to provide relief from chemotherapy-induced pain. BBSRC-funded researchers at King's College London made the discovery when researching ...

User comments : 0

More news stories

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Treating depression in Parkinson's patients

A group of scientists from the University of Kentucky College of Medicine and the Sanders-Brown Center on Aging has found interesting new information in a study on depression and neuropsychological function in Parkinson's ...

Study says we're over the hill at 24

(Medical Xpress)—It's a hard pill to swallow, but if you're over 24 years of age you've already reached your peak in terms of your cognitive motor performance, according to a new Simon Fraser University study.

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...