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Im, W.

Publications and source records attributed to Im, W..

At least 19 recordsLinked to original sources

CHARMM-GUI Covalent Ligand Docker as a Web-based Molecular Docking Platform for Covalent Ligands

Covalent inhibitor research is an emerging topic in drug discovery due to its superior performance in specificity and inhibition effects. While molecular docking is a popular strategy in prediction and assessment of ligand conformations or poses in receptor proteins, covalent ligand docking requires nontrivial preparation efforts, as the ligand structure changes during the covalent complex formation. In order to facilitate molecular docking for covalent ligands, we have developed CHARMM-GUI Covalent Ligand Docker (CGUI-CLD), a new module for covalent ligand docking supported by AutoDock4. CGUI-CLD automates ligand preparation, supports ligand modification, implements docking simulation, and presents results through an intuitive user interface. A knowledge-based library built in CGUI-CLD currently supports 66 warheads and 8 amino acids, which can be used to automate the covalent ligand transformation from a pre-reaction to a post-reaction adduct form seamlessly. Moreover, CHARMM-GUI High-Throughput Simulator is integrated for rapid generation of multiple molecular dynamics simulation systems. CGUI-CLD is expected to significantly reduce a massive workload of covalent ligand docking and advance covalent ligand research. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=111 SRC="FIGDIR/small/738313v1_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@1b79576org.highwire.dtl.DTLVardef@1b579eforg.highwire.dtl.DTLVardef@1584d40org.highwire.dtl.DTLVardef@37bc02_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOAbstract TOCC_FLOATNO C_FIG

biophysics↗

Comparative Analysis of Relative Ligand Binding Free Energy Simulation Methods: Amber-TI, GROMACS-NETI, OpenMM-FEP, and BLaDE-MSLD

Structure-based drug design has become increasingly important in the pharmaceutical industry for accelerating the discovery of effective drug candidates. In particular, ligand binding free energy serves as a critical metric for predicting drug efficacy during the key stages of hit discovery and lead optimization. Continuous progresses have been made in the prediction of ligand binding free energies, but direct comparisons of different methods using the same force field remain challenging due to their unique implementations into different simulation engines. In this study, we present a direct comparison of four popular methodologies (Amber-TI, GROMACS-NETI, OpenMM-FEP, and BLaDE-MSLD) for calculating relative binding free energies ({Delta}{Delta}Gbind) with the same Amber protein and ligand force fields using MolCube Alchemical Free Energy Simulator (MolCube-AFES), which provides an input generation workflow to support {Delta}{Delta}Gbind calculations of all four methods. We used 80 alchemical transformations (among the JACS benchmark set by Wang et al.) and two additional applications to compare the predicted {Delta}{Delta}Gbind from the four methods against experimental measurements. All four methods reproduced experimentally observed trends with most transformations within {+/-}2 kcal/mol from experiments and show broadly comparable accuracy with no statistically significant performance differences across the benchmark dataset. These results demonstrate that MolCube-AFES enables controlled, cross platform benchmarking and show that all four different alchemical free energy methods deliver statistically equivalent accuracy, with method selection guided by workflow requirements such as throughput, portability, and perturbation network design rather than expected differences in performances.

biophysics↗

Influence of Lipomannan and Lipoarabinomannan Concentration on Mycobacterial Inner Membranes Characterized by All-atom Simulations

Mycobacteria are responsible for causing severe illnesses like tuberculosis and leprosy in humans. Studying the mycobacteria cell envelope presents a significant challenge due to its intricate lipid compositions and structural variations and also its harmful nature in a typical experiment setting. In this study, we use all-atom molecular dynamics simulation to study mycobacterial inner membranes (MIMs). By incorporating different types of phosphatidyl-myo-inositol-mannosides (PIMs) and their glycoconjugates such as lipomannans (LM) and lipoarabinomannans (LAM) lipoglycans, we have constructed both symmetric and asymmetric membrane systems to study the MIM structure and dynamics under varying compositions of each lipid type. Our results show that the phospholipid/PIM-rich inner leaflet remains a stable, fluid bilayer, and the outer leaflet structure and dynamics are heavily governed by lipoglycan surface density. Importantly, as LM/LAM concentration increases, the polysaccharide chains shift from flexible, membrane-lying orientations to a compact brush-like state aligned with the membrane normal. This crowding significantly reduces the solvent-accessible volume and limits direct interactions between LM/LAM sugars and the outer leaflet surface. Furthermore, we observe that high lipoglycan presence in the outer leaflet slows lipid diffusion across the entire bilayer, demonstrating a dynamic coupling between the two leaflets. By resolving these LM/LAM sugar-level dynamics and their impact on membrane-wide properties, this study provides a molecular framework for future MIM modeling and simulation with various (peripheral) membrane proteins to better understand how the MIM functions as a regulated physical barrier and a platform for mycobacterial virulence.

biophysics↗

Coarse-Grained Simulations of Mycobacterial Outer Membranes Reveal Fluidity-Dependent PDIM Redistribution Across Different Lipid Environments

The mycobacterial outer membrane (MOM) constitutes an asymmetric permeability barrier that influences lipid organization and transport in Mycobacterium tuberculosis. In this study, we have developed MARTINI 3 coarse-grained (CG) lipid models of the MOM, incorporating -mycolic acids, 5 different trehalose-based lipids, and PDIM (phthiocerol dimycocerosate). The CG models were parameterized and validated using all-atom simulations of symmetric inner- and outer-leaflet membranes, as well as fully asymmetric MOM models. Bonded parameters were optimized through an iterative refinement procedure targeting atomistic bonded distributions. The CG simulations show good agreement with the all-atom simulation data and available experimental measurements in terms of the membrane thickness, solvent accessible surface area, lipid density profiles, and the outer-leaflet-induced lipid disorder in -mycolic acids at the inner leaflet. The model reproduces the temperature-dependent phase behavior of all-atom -mycolic acid membranes. Using this model, we demonstrate that PDIM localization, diffusion, and aggregation are strongly modulated by membrane fluidity and lipid composition, with enhanced translocation and clustering in liquid disordered environments. Our CG MOM lipid models provide a validated platform for large-scale simulations of mycobacterial membranes and enable mechanistic studies of lipid organization, membrane dynamics, and protein-membrane and membrane-drug interactions.

biophysics↗

ST-Analyzer: A Packaged Web and Command-Line Interface for Simulation Trajectory Analysis

As high-performance computing provides the ability to generate and analyze ever larger simulation trajectories, the challenges in learning, applying, and sharing the best analytical practices become more salient. Extracting reproducible scientific insights from simulation requires a thorough understanding of many computing topics unrelated to the molecular systems being modeled and simulated. While the rapid development of the technologies used for analysis makes previously impossible studies into routine work, the growing repertoire of software combined with the specificity of the ecosystems that they rely on can easily break the programs used in older studies. In this work, we present ST-Analyzer, a simulation trajectory analysis suite with command-line (CLI) and graphical (GUI) user interfaces. ST-Analyzer is distributed freely as an open-source conda-forge package with support for macOS, Linux, and Windows (via WSL2). Besides facilitating several common analysis tasks, the GUI shows users the exact commands necessary to repeat the same tasks on the command-line. We demonstrate ST-Analyzers capabilities by reproducing several results from previously published simulation studies on the lipid parameters of heterogeneous biomembranes and the behavior of a SARS-CoV-2 spike protein-antibody complex. We expect ST-Analyzer to be useful to experts for quickly setting up common analysis tasks and to nonexperts as a guided introduction to simulation analysis using both GUI and CLI. ST-Analyzer is freely available at https://github.com/nk53/stanalyzer.

biophysics↗

Conformational Variability of HIV-1 Env Trimer and Viral Vulnerability

HIV-1 envelope glycoprotein (Env) is critical for viral fusion and entry into host cells and remains a primary target for vaccine and antiviral drug development. Advances in soluble gp140 trimer design have provided insight into the ectodomain structure and dynamics. While structural information is available for the membrane-proximal external region (MPER) and transmembrane domain (TMD), these regions remain comparatively understudied. Furthermore, high-resolution structural information for the cytoplasmic tail (CT), particularly within the context of the intact trimer, is limited and largely uncertain. Additionally, previous studies have typically treated the ectodomain and TMD as separate entities. To investigate the trimeric gp120-gp41 as a complete entity and its structural flexibility, we built a full-length model of the gp120-gp41 trimer that is fully glycosylated with N-linked glycans and embedded in a lipid bilayer, and performed all-atom molecular dynamics simulations. Our results show that the ectodomain maintains a rigid internal structure stable in the prefusion state, whereas the intrinsic flexibility of the MPER enables the ectodomain to adopt a range of tilted orientations, potentially enhancing spatial alignment for receptor engagement. The centrally positioned R696 residue in the TMD interacts with lipid headgroups, ions, and CT residues, resulting in conformational variability in the TMD and perturbations in the surrounding membrane that may facilitate the fusion process. Finally, we demonstrate how simulation trajectories can be leveraged to evaluate the accessibility of antibody epitopes across different regions of the protein.

biophysics↗

Interhelical distance measurements support a hairpin conformation for Caveolin-1 in phospholipid bicelles

Previous molecular dynamics (MD) simulations of caveolin-1 (Cav1) in our labs revealed the possibility of two stable conformations of its intramembrane helices (H1 and H2). To distinguish between these two conformations, experimental intramolecular distances obtained using FRET (Forster resonance energy transfer) were integrated into the MD simulations to better define the position of these helices. Two mutants of Cav1 were generated where an acceptor fluorophore, dansyl, was positioned at the N-terminal end and center of H1 (A87C, F99C respectively), while a donor fluorophore, a native tryptophan, was positioned at the C-terminal end of H2 (W128). For the A87C W128 mutant, a distance of 22.5 {+/-} 0.3 [A] was observed while a distance of 24.4 {+/-} 0.2 [A] was observed for the F99C W128 mutant in phospholipid bicelles. These experimental FRET distances were compared to distances in MD simulations of over 100 Cav1 structures. Together these studies support that H1 and H2 adopt a hairpin conformation in bicelles.

biochemistry↗

Dynamic Architecture of Mycobacterial Outer Membranes Revealed by All-Atom Simulations

Tuberculosis remains a global health crisis due to the resilience of Mycobacterium tuberculosis (Mtb), largely attributed to its unique cell envelope. The impermeability and structural complexity of the outer membrane of this envelope, driven by mycolic acids and glycolipids, pose significant challenges for therapeutic intervention. Here, we present the first all-atom models of an Mtb outer membrane using molecular dynamics simulations. We demonstrate that -mycolic acids adopt extended conformations to stabilize bilayers, with a phase transition near 338 K that underscores their thermal resilience. Lipids in the outer leaflet such as PDIM and PAT induce membrane heterogeneity, migrating to the interleaflet space and reducing lipid order. The simulated mycobacterial outer membrane has ordered inner leaflets and disordered outer leaflets, which contrasts with the outer membrane of Gram-negative bacteria. These findings reveal that PDIM- and PAT-driven lipid redistribution, reduced lipid order, and asymmetric fluidity gradients enable Mtbs outer membrane to resist host-derived stresses and limit antibiotic penetration, thereby promoting bacterial survival. Our work provides a foundational framework for targeting the mycobacterial outer membrane in future drug development. TeaserMolecular dynamics simulations reveal the unique architecture of the mycobacterial outer membrane: a fluid outer leaflet and an ordered, tightly packed inner leaflet.

biophysics↗

THE LASSA VIRUS FUSION DOMAIN HAS STRUCTURAL PLASTICITY AND EXPLOITS BIS(MONOACYLGLYCERO)PHOSPHATE FOR FUSION

Infection with Lassa virus (LASV), an arenavirus endemic to West Africa, results in a viral hemorrhagic fever with high mortality rates and public health implications. The glycoprotein complex (GPC) is central to LASVs infectivity as it mediates viral entry via membrane fusion. The fusion domain (FD, G260 - N295) facilitates the initiation of membrane fusion and, thus, the merging of the viral and host cell membranes in a pH-dependent fashion at the lysosomal membrane. The FD consists of two distinct regions: an N-terminal fusion peptide (FP, G260 - T274) and an internal fusion loop (FL, C279 - N295) that are connected by a short linker region (P275 - Y278). Nonetheless, the precise structural and functional characteristics of the LASV FD remain unknown. Here, we demonstrate that the LASV FD associates with the host cell membrane via its FL, specifically residues R282 - L290, whereas the FP is more solvent-exposed, especially for residues D268 - T274. We found that a multitude of conformational states are adopted by the entire LASV FD before membrane association, while only the FP, and not the FL, continues to sample numerous states after membrane association. Moreover, we provide evidence that the LASV FD prefers to interact with anionic lipids, namely bis(monoacylglycero)phosphate (BMP). In conclusion, our findings indicate that the LASV FD preferentially initiates fusion in the presence of BMP, at which point the FL adopts a helical conformation to associate with the membrane, whereas the FP remains exposed to the environment.

biochemistry↗

Identification of chemical features that influence mycomembrane permeation and antitubercular activity

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), is the deadliest single-agent infection worldwide. Current antibiotic treatment for TB takes a minimum of four months, underscoring the need for better therapeutics. The unique mycobacterial cell envelope, particularly the outermost mycomembrane, has long been thought to promote intrinsic antibiotic resistance by limiting compound entry into Mtb. Understanding chemical features that influence permeation across the mycomembrane may enable more accurate predictions of whole cell anti-Mtb activity, leading to development of more effective antibacterials. Here we query the mycomembrane permeation of over 1500 azide-tagged compounds in live Mtb with the bioorthogonal click chemistry-based assay PAC-MAN. We use cheminformatics and machine learning to identify chemical features associated with mycomembrane permeation and show that they have predictive value via systematic modification of two small molecule series. Additionally, we find that chemical features that influence mycomembrane permeation correlate with anti-Mtb activity in large compound libraries. These findings suggest that the mycomembrane is indeed a significant barrier to whole cell activity in Mtb and provide a rational framework for designing or modifying compounds to overcome this barrier.

microbiology↗

Systematic Determination of the Impact of Structural Edits on Accumulation into Mycobacteria

Understanding the factors that influence the accumulation of molecules beyond the mycomembrane of Mycobacterium tuberculosis (Mtb) - the main barrier to accumulation - is essential for developing effective antimycobacterial agents. In this study, we investigated two design principles commonly observed in natural products and mammalian cell-permeable peptides: backbone N-alkylation and macrocyclization. To assess how these structural edits impact molecule accumulation beyond the mycomembrane, we utilized our recently developed Peptidoglycan Accessibility Click-Mediated Assessment (PAC-MAN) assay for live-cell analysis. Our findings provide the first empirical evidence that peptide macrocyclization generally enhances accumulation in mycobacteria, while N-alkylation influences accumulation in a context-dependent manner. We examined these design principles in the context of two peptide antibiotics, tridecaptin A1 and griselimycin, which revealed the roles of N-alkylation and macrocyclization in improving both accumulation and antimicrobial activity against mycobacteria in specific contexts. Together, we present a working model for strategic structural modifications aimed at enhancing the accumulation of molecules past the mycomembrane. More broadly, our results also challenge the prevailing belief in the field that large and hydrophilic molecules, such as peptides, cannot readily traverse the mycomembrane.

microbiology↗

Molecular basis of the urate transporter URAT1 inhibition by gout drugs

Hyperuricemia is a condition when uric acid, a waste product of purine metabolism, accumulates in the blood1. Untreated hyperuricemia can lead to crystal formation of monosodium urate in the joints, causing a painful inflammatory disease known as gout. These conditions are associated with many other diseases and affect a significant and increasing proportion of the population2-4. The human urate transporter 1 (URAT1) is responsible for the reabsorption of [~]90% of uric acid in the kidneys back into the blood, making it a primary target for treating hyperuricemia and gout5. Despite decades of research and development, clinically available URAT1 inhibitors have limitations because the molecular basis of URAT1 inhibition by gout drugs remains unknown5. Here we present cryo-electron microscopy structures of URAT1 alone and in complex with three clinically relevant inhibitors: benzbromarone, lesinurad, and the novel compound TD-3. Together with functional experiments and molecular dynamics simulations, we reveal that these inhibitors bind selectively to URAT1 in inward-open states. Furthermore, we discover differences in the inhibitor dependent URAT1 conformations as well as interaction networks, which contribute to drug specificity. Our findings illuminate a general theme for URAT1 inhibition, paving the way for the design of next-generation URAT1 inhibitors in the treatment of gout and hyperuricemia.

biophysics↗

CHARMM-GUI Multicomponent Assembler for Modeling and Simulation of Complex Multicomponent Systems

Atomic-scale molecular modeling and simulation are powerful tools for computational biology. However, constructing models with large, densely packed molecules, non-water solvents, or with combinations of multiple biomembranes, polymers, and nanomaterials remains challenging and requires significant time and expertise. Furthermore, existing tools do not support such assemblies under the periodic boundary conditions (PBC) necessary for molecular simulation. Here, we describe Multicomponent Assembler in CHARMM-GUI that automates complex molecular assembly and simulation input preparation under the PBC. We demonstrate its versatility by preparing 6 challenging systems with varying density of large components: (1) solvated proteins, (2) solvated proteins with a pre-equilibrated membrane, (3) solvated proteins with a sheet-like nanomaterial, (4) solvated proteins with a sheet-like polymer, (5) a mixed membrane-nanomaterial system, and (6) a sheet-like polymer with gaseous solvent. Multicomponent Assembler is expected to be a unique cyberinfrastructure to facilitate innovative studies of complex interactions between small (organic and inorganic) molecules, biomacromolecules, polymers, and nanomaterials.

biophysics↗

Structural modeling of cytokine-receptor-JAK2 signaling complexes using AlphaFold Multimer

Homodimeric class 1 cytokine receptors include the erythropoietin (EPOR), thrombopoietin (TPOR), granulocyte colony-stimulating factor 3 (CSF3R), growth hormone (GHR), and prolactin receptors (PRLR). They are cell-surface single-pass transmembrane (TM) glycoproteins that regulate cell growth, proliferation, and differentiation and induce oncogenesis. An active TM signaling complex consists of a receptor homodimer, one or two ligands bound to the receptor extracellular domains and two molecules of Janus Kinase 2 (JAK2) constitutively associated with the receptor intracellular domains. Although crystal structures of soluble extracellular domains with ligands have been obtained for all the receptors except TPOR, little is known about the structure and dynamics of the complete TM complexes that activate the downstream JAK-STAT signaling pathway. Three-dimensional models of five human receptor complexes with cytokines and JAK2 were generated using AlphaFold Multimer. Given the large size of the complexes (from 3220 to 4074 residues), the modeling required a stepwise assembly from smaller parts with selection and validation of the models through comparisons with published experimental data. The modeling of active and inactive complexes supports a general activation mechanism that involves ligand binding to a monomeric receptor followed by receptor dimerization and rotational movement of the receptor TM -helices causing proximity, dimerization, and activation of associated JAK2 subunits. The binding mode of two eltrombopag molecules to TM -helices of the active TPOR dimer was proposed. The models also help elucidating the molecular basis of oncogenic mutations that may involve non-canonical activation route. Models equilibrated in explicit lipids of the plasma membrane are publicly available.

biochemistry↗

Molecular basis of polyspecific drug binding and transport by OCT1 and OCT2

A wide range of endogenous and xenobiotic organic ions require facilitated transport systems to cross the plasma membrane for their disposition1, 2. In mammals, organic cation transporter subtypes 1 and 2 (OCT1 and OCT2, also known as SLC22A1 and SLC22A2, respectively) are polyspecific transporters responsible for the uptake and clearance of structurally diverse cationic compounds in the liver and kidneys, respectively3, 4. Notably, it is well established that human OCT1 and OCT2 play central roles in the pharmacokinetics, pharmacodynamics, and drug-drug interactions (DDI) of many prescription medications, including metformin5, 6. Despite their importance, the basis of polyspecific cationic drug recognition and the alternating access mechanism for OCTs have remained a mystery. Here, we present four cryo-EM structures of apo, substrate-bound, and drug-bound OCT1 and OCT2 in outward-facing and outward-occluded states. Together with functional experiments, in silico docking, and molecular dynamics simulations, these structures uncover general principles of organic cation recognition by OCTs and illuminate unexpected features of the OCT alternating access mechanism. Our findings set the stage for a comprehensive structure-based understanding of OCT-mediated DDI, which will prove critical in the preclinical evaluation of emerging therapeutics.

biophysics↗

Anillin Related Mid1 as an Adaptive and Multimodal Contractile Ring Anchoring Protein: A Simulation Study

The organization of the cytokinetic ring at the cell equator of dividing animal and fungi cells depends crucially on the anillin scaffold proteins. In fission yeast, anillin related Mid1 binds to the plasma membrane and helps anchor and organize a medial broad band of cytokinetic nodes, which are the precursors of the contractile ring. Similar to other anillins, Mid1 contains a C terminal globular domain with two potential regions for membrane binding, the Pleckstrin Homology (PH) and C2 domains, and an N terminal intrinsically disordered region that is strongly regulated by phosphorylation. Previous studies have shown that both PH and C2 domains can associate with the membrane, preferring phosphatidylinositol-(4,5)-bisphosphate (PIP2) lipids. However, it is unclear if they can simultaneously bind to the membrane in a way that allows dimerization or oligomerization of Mid1, and if one domain plays a dominant role. To elucidate Mid1s membrane binding mechanism, we used the available structural information of the C terminal region of Mid1 in all-atom molecular dynamics (MD) near a membrane with a lipid composition based on experimental measurements (including PIP2 lipids). The disordered L3 loop of C2, as well as the PH domain, separately bind the membrane through charged lipid contacts. In simulations with the full C terminal region started away from the membrane, Mid1 binds through the L3 loop and is stabilized in a vertical orientation with the PH domain away from the membrane. However, a configuration with both C2 and PH initially bound to the membrane remains associated with the membrane. These multiple modes of binding may reflect Mid1s multiple interactions with membranes and other node proteins, and ability to sustain mechanical forces.

biophysics↗

Lipoprotein sorting to the cell surface via a crosstalk between the Lpt and Lol pathways during outer membrane biogenesis

Lipopolysaccharide (LPS) and lipoprotein, two essential components of the outer membrane (OM) in Gram-negative bacteria, play critical roles in bacterial physiology and pathogenicity. LPS translocation to the OM is mediated by LptDE, yet how lipoproteins sort to the cell surface remains elusive. Here we report the identification of an inventory of lipoproteins that are transported to the cell surface via LptDE. Notably, we determined crystal structures of LptDE from Pseudomonas aeruginosa and its complex with an endogenous Escherichia coli lipoprotein YifL. The paLptDE-YifL structure demonstrates that YifL translocates to the OM via LptDE, in a manner similar to LPS transport. The {beta}-barrel domain serves as a passage for the proteinaceous moiety while its acyl chains are transported outside. Our finding has been corroborated by results from native mass spectrometry, immunofluorescence, and photocrosslinking assays, revealing a unique mechanism through which lipoproteins are translocated across the OM in an ATP- and LPS-dependent manner. Moreover, our study expands the scope of current knowledge of lipoprotein sorting by disclosing a crosstalk between the Lpt and Lol pathways.

microbiology↗

From Molecular Dynamics to Supramolecular Organization: The Role of PIM Lipids in the Originality of the Mycobacterial Plasma Membrane

Mycobacterium tuberculosis (Mtb) is the causative agent of tuberculosis, a disease that claims ~1.5 million lives annually. The current treatment regime is long and expensive, and missed doses contribute to drug resistance. There is much to be understood about the Mtb cell envelope, a complicated barrier that antibiotics need to negotiate to enter the cell. Within this envelope, the plasma membrane is the ultimate obstacle and is proposed to be comprised of over 50% mannosylated phosphatidylinositol lipids (phosphatidyl-myoinositol mannosides, PIMs), whose role in the membrane structure remains elusive. Here we used multiscale molecular dynamics (MD) simulations to understand the structure-function relationship of the PIM lipid family and decipher how they self-organize to drive biophysical properties of the Mycobacterial plasma membrane. To validate the model, we tested known anti-tubercular drugs and replicated previous experimental results. Our results shed new light into the organization of the Mycobacterial plasma membrane and provides a working model of this complex membrane to use for in silico studies. This opens the door for new methods to probe potential antibiotic targets and further understand membrane protein function. O_FIG O_LINKSMALLFIG WIDTH=169 HEIGHT=200 SRC="FIGDIR/small/498153v1_ufig1.gif" ALT="Figure 1"> View larger version (56K): org.highwire.dtl.DTLVardef@102b357org.highwire.dtl.DTLVardef@4c30f8org.highwire.dtl.DTLVardef@22f32aorg.highwire.dtl.DTLVardef@8a6f65_HPS_FORMAT_FIGEXP M_FIG C_FIG

biophysics↗