Effect of Terahertz Electromagnetic Field on the Permeability of Potassium Channel Kv1.2

Abstract

Effect of Terahertz Electromagnetic Field on the Permeability of Potassium Channel Kv1.2 Ding W, Zhao X, Wang H, Wang Y, Liu Y, Gong L, Lin S, Liu C, Li Y. Effect of Terahertz Electromagnetic Field on the Permeability of Potassium Channel Kv1.2. Int J Mol Sci. 2023 Jun 17;24(12):10271. doi: 10.3390/ijms241210271. Abstract In this paper, the influence of external terahertz electromagnetic fields with different frequencies of 4 THz, 10 THz, 15 THz, and 20 THz on the permeability of the Kv1.2 voltage-gated potassium ion channel on the nerve cell membrane was studied using the combined model of the “Constant Electric Field-Ion Imbalance” method by molecular dynamics. We found that although the applied terahertz electric field does not produce strong resonance with the –C=O groups of the conservative sequence T-V-G-Y-G amino acid residue of the selective filter (SF) of the channel, it would affect the stability of the electrostatic bond between potassium ions and the carbonyl group of T-V-G-Y-G of SF, and it would affect the stability of the hydrogen bond between water molecules and oxygen atoms of the hydroxyl group of the 374THR side chain at the SF entrance, changing the potential and occupied states of ions in the SF and the occurrence probability of the permeation mode of ions and resulting in the change in the permeability of the channel. Compared with no external electric field, when the external electric field with 15 THz frequency is applied, the lifetime of the hydrogen bond is reduced by 29%, the probability of the “soft knock on” mode is decreased by 46.9%, and the ion flux of the channel is activated by 67.7%. Our research results support the view that compared to “direct knock-on”, “soft knock-on” is a slower permeation mode. Excerpt Many physiological processes of organisms are closely related to the permeability of ion channels on the cell membrane, such as the maintenance of cell membrane potential, the generation of action potentials, the conduction of nerve signals, the regulation of the central nervous system, heart beating, skeletal muscle contraction, hormone secretion, and so on [1]. Abnormal ion channel permeability usually leads to a variety of diseases, such as cardiovascular and cerebrovascular diseases, neurodegenerative diseases, tumors, etc. These diseases, also known as ion channel defect diseases, are generally considered to be genetic diseases and incurable [1,2,3]. Modern medical research believes that the vibration and rotation frequencies of deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein macromolecules in living organisms are in the frequency range of terahertz electromagnetic field, and the quantum energy of terahertz wave is much lower than the valence electron ionization energy of biological molecules (typical value is several eV) [4,5,6,7,8]. Therefore, it will not directly destroy biomolecules but can affect their conformation and function through nonlinear resonance. This special biological effect may realize the regulation of ion channel permeability [9], which is expected to be used in the treatment of ion channel disease. Open access paper: mdpi.com

AI evidence extraction

Main findings

Using molecular dynamics, external terahertz electric fields (4, 10, 15, 20 THz) were reported to alter ion occupancy/potential states in the selectivity filter and change Kv1.2 permeability. Compared with no external field, a 15 THz field reduced hydrogen-bond lifetime by 29%, decreased the probability of the "soft knock-on" mode by 46.9%, and increased ("activated") ion flux by 67.7%.

Outcomes measured

• Kv1.2 potassium channel permeability/ion flux
• Hydrogen bond lifetime at selectivity filter entrance (water–THR374 hydroxyl oxygen)
• Electrostatic bond stability between K+ ions and carbonyl groups in T-V-G-Y-G selectivity filter
• Ion permeation mode probability ("soft knock-on")

Limitations

• Computational molecular dynamics study ("Constant Electric Field-Ion Imbalance" method); no experimental/clinical validation described in abstract
• Exposure metrics beyond frequency (e.g., field strength, SAR) and exposure duration not reported in abstract
• Results reported for specific channel (Kv1.2) and specific modeled conditions; generalizability not stated

{
    "study_type": "in_vitro",
    "exposure": {
        "band": "THz",
        "source": null,
        "frequency_mhz": null,
        "sar_wkg": null,
        "duration": null
    },
    "population": null,
    "sample_size": null,
    "outcomes": [
        "Kv1.2 potassium channel permeability/ion flux",
        "Hydrogen bond lifetime at selectivity filter entrance (water–THR374 hydroxyl oxygen)",
        "Electrostatic bond stability between K+ ions and carbonyl groups in T-V-G-Y-G selectivity filter",
        "Ion permeation mode probability (\"soft knock-on\")"
    ],
    "main_findings": "Using molecular dynamics, external terahertz electric fields (4, 10, 15, 20 THz) were reported to alter ion occupancy/potential states in the selectivity filter and change Kv1.2 permeability. Compared with no external field, a 15 THz field reduced hydrogen-bond lifetime by 29%, decreased the probability of the \"soft knock-on\" mode by 46.9%, and increased (\"activated\") ion flux by 67.7%.",
    "effect_direction": "mixed",
    "limitations": [
        "Computational molecular dynamics study (\"Constant Electric Field-Ion Imbalance\" method); no experimental/clinical validation described in abstract",
        "Exposure metrics beyond frequency (e.g., field strength, SAR) and exposure duration not reported in abstract",
        "Results reported for specific channel (Kv1.2) and specific modeled conditions; generalizability not stated"
    ],
    "evidence_strength": "very_low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "terahertz",
        "THz electromagnetic field",
        "electric field",
        "Kv1.2",
        "voltage-gated potassium channel",
        "selectivity filter",
        "molecular dynamics",
        "ion flux",
        "permeability",
        "soft knock-on"
    ],
    "suggested_hubs": []
}

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