We provide a high resolution, all-atom, femto-second molecular dynamics (MD) simulation of the passage of K ions and HO molecules through the selectivity filter of the KcsA potassium ion channel, based on first principle physical methods. Our results show that a change in the length of the selectivity filter of as little as 3%, regardless of whether the filter is made longer or shorter, will reduce the K ion current by around 50%. In addition, further squeezing or stretching by about 9% can effectively stop the current.
View Article and Find Full Text PDFWe present a comparison of a classical and a quantum mechanical calculation of the motion of K ions in the highly conserved KcsA selectivity filter motive of voltage gated ion channels. We first show that the de Broglie wavelength of thermal ions is not much smaller than the periodic structure of Coulomb potentials in the nano-pore model of the selectivity filter. This implies that an ion may no longer be viewed to be at one exact position at a given time but can better be described by a quantum mechanical wave function.
View Article and Find Full Text PDFSubject-object relations reflect the relation of phenomenology and physics and are at the centre of interest in brain research and neuro-psychology. The unresolved dichotomy behind this relation is one of the most challenging questions of our time. Setting out from causal modelling I suggest a particular topology for subject-object relations and argue that we can find a physical realization in living organism that provides a continuous transform between both domains.
View Article and Find Full Text PDFIn this paper we present a mechanistic model that integrates subneuronal structures, namely ion channels, membrane fatty acids, lipid rafts, G proteins and the cytoskeleton in a dynamic system that is finely tuned in a healthy brain. We also argue that subtle changes in the composition of the membrane's fatty acids may lead to down-stream effects causing dysregulation of the membrane, cytoskeleton and their interface. Such exquisite sensitivity to minor changes is known to occur in physical systems undergoing phase transitions, the simplest and most studied of them is the so-called Ising model, which exhibits a phase transition at a finite temperature between an ordered and disordered state in 2- or 3-dimensional space.
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