Voltage-gated proton channels (H 1) are expressed in eukaryotes, including basal hexapods and polyneopteran insects. However, currently, there is little known about H 1 channels in insects. A characteristic aspartate (Asp) that functions as the proton selectivity filter (SF) and the RxWRxxR voltage-sensor motif are conserved structural elements in H 1 channels. By analysing Transcriptome Shotgun Assembly (TSA) databases, we found 33 polyneopteran species meeting these structural requirements. Unexpectedly, an unusual natural variation Asp to glutamate (Glu) at SF was found in Phasmatodea and Mantophasmatodea. Additionally, we analysed the expression and function of H 1 in the phasmatodean stick insect Extatosoma tiaratum (Et). EtH 1 is strongly expressed in nervous tissue and shows pronounced inward proton conduction. This is the first study of a natural occurring Glu within the SF of a functional H 1 and might be instrumental in uncovering the physiological function of H 1 in insects.
Background: The pyrazoline insecticides, invented by Philips Duphar in the 1970s, provide excellent control of lepidopterans and coleopterans and introduced a novel mode of action (MoA) as sodium-channel-blocking insecticides, but were not commercialized due to unacceptable persistence. This MoA is less explored, with only two successfully commercialized insecticides derived from the pyrazoline class - the oxadiazine indoxacarb from FMC (developed by DuPont) and the semicarbazone metaflumizone, co-developed by BASF and Nihon Nohyaku.
Results: The design and synthesis of novel pyrazoline insecticides with improved biological efficacy and favorable environmental fate profile are described.
Voltage-clamp fluorometry (VCF) combines electrophysiology and fluorescence to study ion channels, providing real-time insights into their structural changes and functions.*
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Acid-sensing ion channels (ASICs) play a key role in detecting pH changes, impacting pain, fear, learning, and neurodegeneration post-stroke, as demonstrated in animal studies.*
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The review details VCF's techniques, including fluorescence resonance energy transfer and unnatural fluorescent amino acids, and highlights how VCF has revealed conformational changes in ASICs, enhancing our understanding of their functional states.*
Here we present the first successful hydrotrifluoromethylation of unactivated olefins under electrochemical conditions. Commercially available trifluoromethyl thianthrenium salt (TT-CFBF , E=-0.85 V vs Fc/Fc) undergoes electrochemical reduction to generate CF radicals which add to olefins with exclusive chemoselectivity.
The voltage-gated proton channel (Hv) facilitates proton transport in response to electrochemical gradients and is significantly influenced by temperature, showing expression in immune cells and human sperm.
Hv’s structure includes an N-terminal cytoplasmic domain, a voltage sensor domain (VSD), and a C-terminal coiled-coil domain, with proton movement regulated by both membrane potential and pH differences.
The coiled-coil domain of Hv is crucial for its temperature sensitivity and gating mechanisms, as mutations in this area can alter temperature thresholds, which affects Hv's physiological roles.
Department of Chemistry, Chicago Center for Theoretical Chemistry, Institute for Biophysical Dynamics, and James Frank Institute, University of Chicago, Chicago, IL 60637.
Human voltage-gated proton (hHv1) channels are crucial for regulating essential biological processes such as immune cell respiratory burst, sperm capacitation, and cancer cell migration. Despite the significant concentration difference between protons and other ions in physiological conditions, hHv1 demonstrates remarkable proton selectivity. Our calculations of single-proton, cation, and anion permeation free energy profiles quantitatively demonstrate that the proton selectivity of the wild-type channel originates from its strong proton affinity via the titration of the key residues D112 and D174, although the channel imposes similar kinetic blocking effects for protons compared to other ions.
