A5029506236- Ion channel regulation and function
- Neuroscience and Neuropharmacology Research
- Molecular Sensors and Ion Detection
- Lipid Membrane Structure and Behavior
- Receptor Mechanisms and Signaling
- Amino Acid Enzymes and Metabolism
- Photoreceptor and optogenetics research
- Adenosine and Purinergic Signaling
- Cardiac electrophysiology and arrhythmias
- Protein Structure and Dynamics
- 14-3-3 protein interactions
- Electrochemical Analysis and Applications
- Chemical Synthesis and Analysis
- Mass Spectrometry Techniques and Applications
- Genetic Neurodegenerative Diseases
- GABA and Rice Research
- Neuroscience and Neural Engineering
- DNA and Nucleic Acid Chemistry
- Calcium signaling and nucleotide metabolism
- Origins and Evolution of Life
- Biomedical Research and Pathophysiology
- Gastroesophageal reflux and treatments
- Bipolar Disorder and Treatment
- Lipid metabolism and biosynthesis
- Pharmacological Receptor Mechanisms and Effects
RWTH Aachen University
2019-2023
Forschungszentrum Jülich
2014-2023
Universitätsklinikum Aachen
2020-2023
Jülich Aachen Research Alliance
2020-2022
Medizinische Hochschule Hannover
2010-2019
Max Planck Institute for Biophysical Chemistry
2015
Institute of Molecular Biology and Biophysics
2014
Robert Bosch (India)
2012
German Centre for Higher Education Research and Science Studies
2010
Abstract Recently, two groups of rhodopsin genes were identified in large double-stranded DNA viruses. The structure and function viral rhodopsins are unknown. We present functional characterization high-resolution an Organic Lake Phycodnavirus II (OLPVRII) group 2. It forms a pentamer, with symmetrical, bottle-like central channel the narrow vestibule cytoplasmic part covered by ring 5 arginines, whereas phenylalanines form hydrophobic barrier its exit. proton donor E42 is placed helix B....
In the mammalian retina, glutamate uptake is mediated by members of a family transporters known as "excitatory amino acid (EAATs)." Here we cloned and functionally characterized two retinal EAATs from mouse, GLT-1/EAAT2 splice variant GLT-1c, EAAT5. are anion-selective ion channels, used heterologous expression in cells, patch-clamp recordings noise analysis to study compare transport anion channel properties both EAAT isoforms. We found GLT-1c be an effective transporter with high affinity...
G-protein-coupled receptors (GPCRs) form the largest superfamily of membrane proteins and one-third all drug targets in humans. A number recent studies have reported evidence for substantial voltage regulation GPCRs. However, structural basis GPCR sensing has remained enigmatic. Here, we present atomistic simulations on δ-opioid M2 muscarinic receptors, which suggest a mechanistic explanation observed voltage-induced functional effects. The reveal that position an internal Na(+) ion,...
Excitatory amino acid transporters (EAATs) are a class of glutamate that terminate glutamatergic synaptic transmission in the mammalian CNS. GltPh, an archeal EAAT homolog from Pyrococcus horikoshii, is currently only member with known 3D structure. Here, we studied kinetics substrate binding single tryptophan mutant (L130W) GltPh detergent micelles. At low millimolar [Na(+)], addition L-aspartate resulted complex time courses W130 fluorescence changes over tens seconds. With increasing were...
Article10 September 2019Open Access Transparent process Allosteric gate modulation confers K+ coupling in glutamate transporters Daniel Kortzak orcid.org/0000-0001-9098-3466 Institute of Complex Systems, Zelluläre Biophysik (ICS-4) and JARA-HPC, Forschungszentrum Jülich, Germany Search for more papers by this author Claudia Alleva Ingo Weyand David Ewers Klinik für klinische Neurophysiologie, Universitätsmedizin Göttingen, Abteilung Neurogenetik, Max-Planck-Institut Experimentelle Medizin,...
Excitatory amino acid transporters (EAATs) harness [Na+], [K+], and [H+] gradients for fast efficient glutamate removal from the synaptic cleft. Since each is cotransported with three Na+ ions, [Na+] are predominant driving force uptake. We combined all-atom molecular dynamics simulations, fluorescence spectroscopy, x-ray crystallography to study Na+:substrate coupling in EAAT homolog GltPh A lipidic cubic phase crystal structure of wild-type, Na+-only bound at 2.5-Å resolution revealed...
Abstract TMEM16 lipid scramblases transport lipids and also operate as ion channels with highly variable selectivities various physiological functions. However, their molecular mechanisms of conduction selectivity remain largely unknown. Using computational electrophysiology simulations at atomistic resolution, we identified the main ion-conductive state scramblases, in which an permeation pathway is lined by headgroups that directly interact permeating ions a voltage polarity-dependent...
Excitatory amino acid transporter (EAAT) glutamate transporters function not only as secondary active but also anion channels. Recently, a conserved aspartic (Asp112) within the intracellular loop near to end of transmembrane domain 2 was proposed major determinant substrate-dependent gating channel associated with glial EAAT1. We studied corresponding mutation (D117A) in another EAAT isoform, EAAT4, using heterologous expression mammalian cells, whole cell patch clamp, and noise analysis....
Abstract The outstanding acuity of the mammalian ear relies on cochlear amplification, an active mechanism based electromotility (eM) outer hair cells. eM is a piezoelectric generated by little-understood, voltage-induced conformational changes anion transporter homolog prestin (SLC26A5). We used combination molecular dynamics (MD) simulations and biophysical approaches to identify structural that mediate eM. MD showed samples vast landscape with expanded (ES) compact (CS) states beyond...
Excitatory amino acid transporter 2 (EAAT2) is a high affinity glutamate predominantly expressed in astroglia. Human EAAT2 encompasses eight transmembrane domains and 74-amino C-terminal domain that resides the cytoplasm. We examined role of this region by studying various truncations mutations using heterologous expression mammalian cells, whole-cell patch clamp recording confocal imaging. Removal complete C terminus (K498X EAAT2) results loss function because intracellular retention...
Background and Purpose The voltage‐gated sodium channel Na v 1.7 is essential for adequate perception of painful stimuli. Mutations in the encoding gene, SCN9A , cause various pain syndromes humans. hNa 1.7/A1632E mutant causes symptoms erythromelalgia paroxysmal extreme disorder (PEPD), its main gating change a strongly enhanced persistent current. On basis recently published 3D structures channels, we investigated how inactivation particle binds to channel, this mechanism altered by...
Abstract Mutations in the muscle chloride channel gene ( CLCN1 ) cause myotonia congenita, an inherited condition characterized by stiffness upon sudden forceful movement. We here studied functional consequences of four disease-causing mutations that predict amino acid substitutions Q43R, S70L, Y137D and Q160H. Wild-type (WT) mutant hClC-1 channels were heterologously expressed as YFP or CFP fusion protein HEK293T cells analyzed whole-cell patch clamp fluorescence recordings on individual...
EAAT glutamate transporters do not only function as secondary-active but also anion channels. channel activity depends on transport substrates. For most isoforms, it is negligible without external Na(+) and increased by glutamate. We here investigated gating of EAAT4 channels with various cations amino acid substrates using patch clamp experiments a mammalian cell line. demonstrate that Li(+) can substitute for in supporting substrate-activated currents, albeit changed voltage dependence....
The voltage-gated sodium channel Nav1.7 is a key player in neuronal excitability and pain signalling. In addition to voltage sensing, the also modulated by mechanical stress. Using whole-cell patch-clamp experiments, we discovered that subunit β1 able prevent impact of stress on Nav1.7. An intramolecular disulfide bond was identified be essential for stabilisation inactivation, but not activation, against using molecular dynamics simulations, homology modelling site-directed mutagenesis. Our...
Introduction: The P2X3 receptor (P2X3R), an ATP-gated non-selective cation channel of the P2X family, is expressed in sensory neurons and involved nociception. P2X3R inhibition was shown to reduce chronic neuropathic pain. In a previous screening 2000 approved drugs, natural products, bioactive substances, various non-steroidal anti-inflammatory drugs (NSAIDs) were found inhibit P2X3R-mediated currents. Methods: To investigate whether receptors contributes analgesic effect NSAIDs, we...
Excitatory amino acid transporters (EAATs) do not only mediate secondary-active glutamate uptake but also function as anion channels. We recently used macroscopic current recordings and noise analysis to determine unitary amplitudes of channels associated with a neuronal EAAT isoform, EAAT4. found that, at symmetrical NO3-, EAAT4 exhibit single channel conductance ~1 pS in the absence well presence glutamate. These results indicate that increases currents by modifying exclusively open...
Electrostatic forces drive a wide variety of biomolecular processes by defining the energetics interaction between biomolecules and charged substances. Molecular dynamics (MD) simulations provide trajectories that contain ensembles structural configurations sampled their environment. Although this information can be used for high-resolution characterization electrostatics, it has not yet been possible to calculate electrostatic potentials from MD in way allowing quantitative connection...