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- Research DataSingle-molecule dynamics reveal ATP binding alone powers substrate translocation by an ABC transporter2025-07-25ATP-binding cassette (ABC) transporters are molecular machines involved in diverse physiological processes, including antigen processing by TAP, a key component of adaptive immunity. TAP and its bacterial homolog TmrAB use ATP to translocate peptides across membranes, yet the precise mechanism linking ATP binding to substrate movement remains unclear. Here, we employ a single-molecule FRET sensor to visualize single translocation events by individual ABC transporters, overcoming the limitations of ensemble averaging. This approach reveals that substrate transport is driven by a conformational switch from the inward- to the outward-facing state. Using a slow-turnover TmrAB variant, we demonstrate that ATP binding alone, even in the absence of Mg2+, is sufficient to drive a single round of peptide translocation. Cryo-EM structures of wild-type and slow-turnover TmrAB show that ATP binding induces the outward-facing conformation without Mg2+. In wild-type TmrAB, this conformational transition supports a single translocation event, whereas Mg2+-dependent ATP hydrolysis is required to reset the transporter. These findings establish a direct mechanistic link between ATP binding and substrate translocation at single-molecule resolution, providing new insights into the catalytic cycle of ABC transporters.
5 2 - Research DataArchitectural principles of transporter-chaperone coupling within the native MHC I peptide-loading complex2025-11-25Adaptive immunity depends on major histocompatibility complex class I (MHC I) presentation of peptides, a process orchestrated by the peptide-loading complex (PLC) in the endoplasmic reticulum. The PLC ensures precise peptide selection and loading and is a major target of viral immune evasion, notably by human cytomegalovirus (HCMV). Here, we report the 2.59–2.88 Å cryo-electron microscopy structure of native human PLC bound to the HCMV immune evasin US6. US6 inhibits the TAP1/2 transporter by laterally attaching its transmembrane helix to TAP2 using a disulfide-rich domain to mimic a translocating peptide. This domain blocks the ER-lumenal exit and locks TAP in an outward-facing conformation with closed nucleotide-binding domains and asymmetric ATP/ADP occlusion. The structure also reveals how TAP’s N-terminal transmembrane domains scaffold the MHC I chaperone tapasin. These findings elucidate the mechanism of US6-mediated immune evasion and highlight potential targets for therapeutic modulation of immune presentation in infection and cancer.
17 1 - Research DataMultistate Dihydroazulene-Spiropyran Dyads: Path-Dependent Switchings and Refinement of the “Meta-rule” of Photoactivity2025-04-08Multistate switches are interesting systems for a plethora of potential applications, such as for data storage involving many different states or for logic operations characterized by specific outputs. The main challenge is to achieve a precise control of accessibility to a specific state via a given sequence of multiple stimuli. Here, we have connected dihydroazulene (DHA) and spiropyran (SP) photoswitches in dyads to elucidate differences in optical and switching properties between ortho-, meta-, and para-phenylene-bridged dyads. Dyads were prepared by Suzuki and Sonogashira coupling reactions and photoisomerizations studied in detail by stationary and ultrafast spectroscopies. Moreover, the kinetics of thermal back-reactions of meta-stable states were studied. The results show path-dependent switchings of the dyads using light in combination with other stimuli (acid/base/heat), allowing access to eight distinct states. The accessibility to some specific states via only one sequence of external stimuli provides an additional degree of data storage—information is not only stored as the state itself but also as the unique sequence of stimuli required to reach this state. By changing the bridging unit between the photoswitches, various properties (outputs) were finely tuned such as absorption and fluorescence behaviors, lifetime of meta-stable state, and photoisomerization dynamics.
15 1 - Research DataGrowth-Controlled Twinning and Magnetic Anisotropy in CeSb22025-11-14Cerium diantimonide (CeSb2) is a layered heavy-fermion Kondo lattice material that hosts complex magnetism and pressure-induced superconductivity. The interpretation of its in-plane anisotropy has remained unsettled due to structural twinning, which superimposes orthogonal magnetic responses. Here we combine controlled crystal growth with magnetization and rotational magnetometry to disentangle the effects of twinning. Nearly untwinned high-quality single crystals reveal the intrinsic in-plane anisotropy: the in-plane easy axis saturates at M_easy(4 T) ≈ 1.8 µ_B/Ce, while the in-plane hard axis magnetization is strongly suppressed, nearly linear, and comparable to the out-of-plane response. These results resolve long-standing discrepancies in reported magnetic measurements, in which in-plane metamagnetic transition fields and saturation magnetization varied significantly across previous studies. Growth experiments demonstrate that avoiding the proposed α-β structural transition - through Sb-rich flux and slower cooling - systematically reduces twinning. However, powder X-ray diffraction and differential thermal analysis measurements show no clear evidence of a distinct β phase. Our results establish a consistent magnetic phase diagram and provide essential constraints for crystal-electric field models, enabling a clearer understanding of the interplay between anisotropic magnetism and unconventional superconductivity in CeSb2.
3 15 - Research DataReconstitution of glycan-driven MHC I recycling reveals calreticulin as mediator between TAPBPR and tapasin2025-04-24Protein folding in the endoplasmic reticulum (ER) is essential for about one-third of the mammalian proteome. N-linked glycosylation and subsequent glycan remodeling barcodes glycoproteins during their maturation in the ER. Major histocompatibility complex class I (MHC I) molecules, key for adaptive immunity, rely on a dedicated quality control cycle that involves specialized chaperones and glycan-modifying enzymes for their maturation and loading of immunogenic peptides. However, the functional interplay of the MHC I editors tapasin as part of the peptide-loading complex (PLC), TAP-binding protein-related (TAPBPR), the UDP-glucose:glycoprotein glucosyltransferase 1 (UGGT1), and calreticulin in glycan-dependent transfer of MHC I clients has not been determined in a reconstituted system. With isolated components, we show that transfer of peptide-receptive MHC I from the downstream quality control factor TAPBPR back to tapasin depends on the recognition of the monoglucosylated glycan of MHC I by calreticulin. While calreticulin’s C-terminal acidic helix is dispensable for disengaging reglucosylated MHC I from TAPBPR, it is essential for docking MHC I onto tapasin. Our data provide a mechanistic basis for glycan-surveillance by calreticulin necessary for retrograde trafficking of misfolded or suboptimally loaded MHC I that escaped the first quality control at the PLC and were trapped by TAPBPR. Such finetuned dynamic network of glycan-dependent and MHC I-specific chaperones guarantees maturation of MHC I molecules and highlight the fundamental processes driving ER protein quality control.
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- Research DataThe global water resources and use model WaterGAP v2.2e - model output driven by gswp3-w5e5 and historical setup of direct human impacts2023-10-20Trautmann, TimAckermann, SebastianCáceres, DeniseFlörke, MartinaGerdener, HelenaKynast, EllenPeiris, Thedini AsaliSchiebener, LeonieSchumacher, MaikeAssessing global freshwater resources and human water use is of value for a number of needs but challenging. The global water use and water availability model WaterGAP has been in development since 1996 and has served a range of applications such as assessments of global water resources and water stress, also under the impact of climate change, drought hazard quantification, Life Cycle Assessments, water (over)use and consequently depletion of water resources and a better understanding of terrestrial water storage variations (jointly with satellite observations). Here, the reader can download model output for the time period 1901-2019 that was computed by driving WaterGAP v2.2e by four alternative climate datasets (climate forcings) that were generated in the ISIMIP context (https://www.isimip.org) and are described in https://data.isimip.org/10.48364/ISIMIP.982724. For two climate datasets, model runs up to 2021 or 2022 are available. For comparison, output of a version of WaterGAP v2.2d that is calibrated to the same dataset of observed streamflow as WaterGAP v2.2e is provided. Each of the climate forcing-model version combinations is run in two socio-economic settings, histsoc and nosoc. In nosoc, human water use is set to zero and man-made reservoirs are assumed to be non-existant. In the paper connected to this dataset (to be submitted to Geoscientific Model Development), the newest model version, WaterGAP v2.2e is described by providing the modifications to the previous version v2.2d (Müller Schmied et al. 2021) and the corresponding changes in model output. The most important and requested model outputs (total water storage variations, streamflow and water use) are evaluated against observation data. Standard model output is described as well as the specifics of the WaterGAP contribution within the ISIMIP framework. Müller Schmied, H., Cáceres, D., Eisner, S., Flörke, M., Herbert, C., Niemann, C., Peiris, T. A., Popat, E., Portmann, F. T., Reinecke, R., Schumacher, M., Shadkam, S., Telteu, C.-E., Trautmann, T., Döll, P. (2021): The global water resources and use model WaterGAP v2.2d: Model description and evaluation. Geosci. Model Dev., 14, 1037–1079. https://doi.org/10.5194/gmd-14-1037-2021
1224 695 - Research DataThe global water resources and use model WaterGAP v2.2e - model output driven by gswp3-era5 and historical setup of direct human impacts2023-10-20Trautmann, TimAckermann, SebastianCáceres, DeniseFlörke, MartinaGerdener, HelenaKynast, EllenPeiris, Thedini AsaliSchiebener, LeonieSchumacher, MaikeAssessing global freshwater resources and human water use is of value for a number of needs but challenging. The global water use and water availability model WaterGAP has been in development since 1996 and has served a range of applications such as assessments of global water resources and water stress, also under the impact of climate change, drought hazard quantification, Life Cycle Assessments, water (over)use and consequently depletion of water resources and a better understanding of terrestrial water storage variations (jointly with satellite observations). Here, the reader can download model output for the time period 1901-2019 that was computed by driving WaterGAP v2.2e by four alternative climate datasets (climate forcings) that were generated in the ISIMIP context (https://www.isimip.org) and are described in https://data.isimip.org/10.48364/ISIMIP.982724. For two climate datasets, model runs up to 2021 or 2023 are available. For comparison, output of a version of WaterGAP v2.2d that is calibrated to the same dataset of observed streamflow as WaterGAP v2.2e is provided. Each of the climate forcing-model version combinations is run in two socio-economic settings, histsoc and nosoc. In nosoc, human water use is set to zero and man-made reservoirs are assumed to be non-existant. In the paper connected to this dataset (in review with Geoscientific Model Development), the newest model version, WaterGAP v2.2e is described by providing the modifications to the previous version v2.2d (Müller Schmied et al. 2021) and the corresponding changes in model output. The most important and requested model outputs (total water storage variations, streamflow and water use) are evaluated against observation data. Standard model output is described as well as the specifics of the WaterGAP contribution within the ISIMIP framework. Müller Schmied, H., Cáceres, D., Eisner, S., Flörke, M., Herbert, C., Niemann, C., Peiris, T. A., Popat, E., Portmann, F. T., Reinecke, R., Schumacher, M., Shadkam, S., Telteu, C.-E., Trautmann, T., Döll, P. (2021): The global water resources and use model WaterGAP v2.2d: Model description and evaluation. Geosci. Model Dev., 14, 1037–1079. https://doi.org/10.5194/gmd-14-1037-2021
725 795 - Research DataA j_eff 12 Kitaev material on the triangular lattice: The case of NaRuO22023-06-07Motivated by recent reports of a quantum disordered ground state in the triangular lattice compound NaRuO$_2$, we derive a $j_{\rm eff}=1/2$ magnetic model for this system by means of first-principles calculations. The pseudospin Hamiltonian is dominated by bond-dependent off-diagonal $\Gamma$ interactions, complemented by a ferromagnetic Heisenberg exchange and a notably \emph{antiferromagnetic} Kitaev term. In addition to bilinear interactions, we find a sizable four-spin ring exchange contribution with a \emph{strongly anisotropic} character, which has been so far overlooked when modeling Kitaev materials. The analysis of the magnetic model, based on the minimization of the classical energy and exact diagonalization of the quantum Hamiltonian, points toward the existence of a rather robust easy-plane ferromagnetic order, which cannot be easily destabilized by physically relevant perturbations.
355 39 - Research DataThe global water resources and use model WaterGAP v2.2e - daily water storage model output driven by gswp3-era5 and historical setup of direct human impacts2024-04-04Trautmann, TimAckermann, SebastianCáceres, DeniseFlörke, MartinaGerdener, HelenaKynast, EllenPeiris, Thedini AsaliSchiebener, LeonieSchumacher, MaikeAssessing global freshwater resources and human water use is of value for a number of needs but challenging. The global water use and water availability model WaterGAP has been in development since 1996 and has served a range of applications such as assessments of global water resources and water stress, also under the impact of climate change, drought hazard quantification, Life Cycle Assessments, water (over)use and consequently depletion of water resources and a better understanding of terrestrial water storage variations (jointly with satellite observations). Here, the reader can download daily model output for water storage variables for the time period 1901-2019 (2023) that was computed by driving WaterGAP v2.2e by two alternative climate datasets (climate forcings) that were generated in the ISIMIP context (https://www.isimip.org) and are described in https://data.isimip.org/10.48364/ISIMIP.982724. In the paper connected to this dataset (in review with Geoscientific Model Development), the newest model version, WaterGAP v2.2e is described by providing the modifications to the previous version v2.2d (Müller Schmied et al. 2021) and the corresponding changes in model output. Here, the single water storage compartments and terrestrial (total) water storage are provided.
306 148 - Research DataThe global water resources and use model WaterGAP v2.2d - model output driven by gswp3-w5e5 and historical setup of direct human impacts2023-10-20Trautmann, TimAckermann, SebastianCáceres, DeniseFlörke, MartinaGerdener, HelenaKynast, EllenPeiris, Thedini AsaliSchiebener, LeonieSchumacher, MaikeAssessing global freshwater resources and human water use is of value for a number of needs but challenging. The global water use and water availability model WaterGAP has been in development since 1996 and has served a range of applications such as assessments of global water resources and water stress, also under the impact of climate change, drought hazard quantification, Life Cycle Assessments, water (over)use and consequently depletion of water resources and a better understanding of terrestrial water storage variations (jointly with satellite observations). Here, the reader can download model output for the time period 1901-2019 that was computed by driving WaterGAP v2.2e by four alternative climate datasets (climate forcings) that were generated in the ISIMIP context (https://www.isimip.org) and are described in https://data.isimip.org/10.48364/ISIMIP.982724. For two climate datasets, model runs up to 2021 or 2022 are available. For comparison, output of a version of WaterGAP v2.2d that is calibrated to the same dataset of observed streamflow as WaterGAP v2.2e is provided. Each of the climate forcing-model version combinations is run in two socio-economic settings, histsoc and nosoc. In nosoc, human water use is set to zero and man-made reservoirs are assumed to be non-existant. In the paper connected to this dataset (to be submitted to Geoscientific Model Development), the newest model version, WaterGAP v2.2e is described by providing the modifications to the previous version v2.2d (Müller Schmied et al. 2021) and the corresponding changes in model output. The most important and requested model outputs (total water storage variations, streamflow and water use) are evaluated against observation data. Standard model output is described as well as the specifics of the WaterGAP contribution within the ISIMIP framework. Müller Schmied, H., Cáceres, D., Eisner, S., Flörke, M., Herbert, C., Niemann, C., Peiris, T. A., Popat, E., Portmann, F. T., Reinecke, R., Schumacher, M., Shadkam, S., Telteu, C.-E., Trautmann, T., Döll, P. (2021): The global water resources and use model WaterGAP v2.2d: Model description and evaluation. Geosci. Model Dev., 14, 1037–1079. https://doi.org/10.5194/gmd-14-1037-2021
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