On the classical vibrational coherence of carbonyl groups in the selectivity filter backbone of the KcsA ion channel

Abstract

It has been suggested that quantum coherence in the selectivity filter of ion channel may play a key role in fast conduction and selectivity of ions. However, it has not been clearly elucidated yet why classical coherence is not sufficient for this purpose. In this paper, we investigate the classical vibrational coherence between carbonyl groups oscillations in the selectivity filter of KcsA ion channels based on the data obtained from molecular dynamics simulations. Our results show that classical coherence plays no effective role in fast ionic conduction.

Quantum Interference and Selectivity through Biological Ion Channels

“…λ dB = h/ mv where h is the Planck’s cnstant, m is the mass of ion, and v is the velocity of ion) inside the selectivity filter via molecular dynamics (MD) simulation. In fact, our method (see Supplementary Information ) is the same as what we used previously 17 20 but we use it here with higher cutoffs, i.e. 1 nm for the van der Waals interaction and 1 nm for electrostatic interactions.…”

“…Taking typical values for membrane potentials in neurons, −70 mV and +30 mV, for resting and firing states are considered 30 31 . To be more general, we also considered other membrane potentials −100 mV and +100 mV 32 to obtain other velocities as well 17 20 . The obtained results are shown in the Table 1 , in which the order of the wavelength of ions ( λ 0 ≈ 0.1 nm) is the same as the order of the width of each slit (i.e.…”

“… (Left) A representation of KcsA ion channel. (Right) Two P-loop monomers in the selectivity filter, composed of the sequences of TVGYG amino acids [T(Threonine, Thr75), V(Valine, Val76), G(Glycine, Gly77), Y(Tyrosine, Tyr78), G(Glycine, Gly79)] linked by peptide units H-N-C =O 20 . …”

“… We have chosen the typical values for membrane potentials in neurons, −70 mV and +30 mV, for resting and firing states as well as −100 mV and +100 mV for a general state 17 20 . …”

“…The living cell is an information replicating and processing system that is replete with naturally-evolved nanomachines, which at some level may require a quantum mechanical description despite critical limitations for application of quantum theory in biology 13 . In this case, ion channels are good examples in living cells in which quantum effects may play a role 14 15 16 17 18 19 20 . They are proteins in the membrane of cells that can cooperate for the onset and propagation of electrical signals across membranes by providing a highly selective conduction of charges bound to ions through a channel like structure.…”