Journal of Structural Biology: X最新文献

{"title":"The parabasal filaments of Trichomonas vaginalis: A new filament and observations using 0.8 nm-resolution scanning electron microscopy","authors":"Sharmila Fiama das Neves Ortiz ,&nbsp;Raphael Verdan ,&nbsp;Gustavo Miranda Rocha ,&nbsp;Kildare Miranda ,&nbsp;Marlene Benchimol","doi":"10.1016/j.yjsbx.2024.100099","DOIUrl":"https://doi.org/10.1016/j.yjsbx.2024.100099","url":null,"abstract":"<div><p><em>Trichomonas vaginalis</em> is the etiologic agent of trichomoniasis, the most common nonviral sexually transmitted infection worldwide, with an estimated 260 million new cases annually. <em>T. vaginalis</em> contains organelles common to all eukaryotic cells, uncommon cell structures such as hydrogenosomes, and a complex and elaborate cytoskeleton constituting the mastigont system. The mastigont system is mainly formed by several proteinaceous structures associated with basal bodies, the pelta-axostylar complex made of microtubules, and striated filaments named the costa and the parabasal filaments (PFs). Although the structural organization of trichomonad cytoskeletons has been analyzed using several techniques, observation using a new generation of scanning electron microscopes with a resolution exceeding 1 nm has allowed more detailed visualization of the three-dimensional organization of the mastigont system. In this study, we have investigated the cytoskeleton of <em>T. vaginalis</em> using a diverse range of scanning probe microscopy techniques, which were complemented by electron tomography and Fast-Fourier methods. This multi-modal approach has allowed us to characterize an unknown parabasal filament and reveal the ultrastructure of other striated fibers that have not been published before. Here, we show the differences in origin, striation pattern, size, localization, and additional details of the PFs, thus improving the knowledge of the cell biology of this parasite.</p></div>","PeriodicalId":17238,"journal":{"name":"Journal of Structural Biology: X","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590152424000047/pdfft?md5=f5be6fd3381454e5b294408c8f1c6d0c&pid=1-s2.0-S2590152424000047-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140051590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magic-angle spinning NMR structure of Opa60 in lipid bilayers","authors":"Marcel C. Forster,&nbsp;Kumar Tekwani Movellan,&nbsp;Eszter E. Najbauer,&nbsp;Stefan Becker,&nbsp;Loren B. Andreas","doi":"10.1016/j.yjsbx.2024.100098","DOIUrl":"https://doi.org/10.1016/j.yjsbx.2024.100098","url":null,"abstract":"<div><p>Here we report the structure of Opa60 in lipid bilayers using proton-detected magic-angle spinning nuclear magnetic resonance (MAS NMR). Preparations including near-native oligosaccharide lipids reveal a consistent picture of a stable transmembrane beta barrel with a minor increase in the structured region as compared with the previously reported detergent structure. The large variable loops known to interact with host proteins could not be detected, confirming their dynamic nature even in a lipid bilayer environment. The structure provides a starting point for investigation of the functional role of Opa60 in gonococcal infection, which is understood to involve interaction with host proteins. At the same time, it demonstrates the recent advances in proton-detected methodology for membrane protein structure determination at atomic resolution by MAS NMR.</p></div>","PeriodicalId":17238,"journal":{"name":"Journal of Structural Biology: X","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590152424000035/pdfft?md5=bcfa30af962cd69ec03183b9f0718283&pid=1-s2.0-S2590152424000035-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140015902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Grafting the ALFA tag for structural studies of aquaporin Z","authors":"Lauren Stover ,&nbsp;Hanieh Bahramimoghaddam ,&nbsp;Lie Wang ,&nbsp;Samantha Schrecke ,&nbsp;Gaya P. Yadav ,&nbsp;Ming Zhou ,&nbsp;Arthur Laganowsky","doi":"10.1016/j.yjsbx.2024.100097","DOIUrl":"https://doi.org/10.1016/j.yjsbx.2024.100097","url":null,"abstract":"<div><p>Aquaporin Z (AqpZ), a bacterial water channel, forms a tetrameric complex and, like many other membrane proteins, activity is regulated by lipids. Various methods have been developed to facilitate structure determination of membrane proteins, such as the use of antibodies. Here, we graft onto AqpZ the ALFA tag (AqpZ-ALFA), an alpha helical epitope, to make use of the high-affinity anti-ALFA nanobody (nB). Native mass spectrometry reveals the AqpZ-ALFA fusion forms a stable, 1:1 complex with nB. Single-particle cryogenic electron microscopy studies reveal the octameric (AqpZ-ALFA)₄(nB)₄ complex forms a dimeric assembly and the structure was determined to 1.9 Å resolution. Dimerization of the octamer is mediated through stacking of the symmetrically bound nBs. Tube-like density is also observed, revealing a potential cardiolipin binding site. Grafting of the ALFA tag, or other epitope, along with binding and association of nBs to promote larger complexes will have applications in structural studies and protein engineering.</p></div>","PeriodicalId":17238,"journal":{"name":"Journal of Structural Biology: X","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590152424000023/pdfft?md5=81782f0ee174ad218a60122e91b9a015&pid=1-s2.0-S2590152424000023-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139714608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structure of biomimetic casein micelles: Critical tests of the hydrophobic colloid and multivalent-binding models using recombinant deuterated and phosphorylated β-casein","authors":"Jared K. Raynes ,&nbsp;Jitendra Mata ,&nbsp;Karyn L. Wilde ,&nbsp;John A. Carver ,&nbsp;Sharon M. Kelly ,&nbsp;Carl Holt","doi":"10.1016/j.yjsbx.2024.100096","DOIUrl":"10.1016/j.yjsbx.2024.100096","url":null,"abstract":"<div><p>Milk contains high concentrations of amyloidogenic casein proteins and is supersaturated with respect to crystalline calcium phosphates such as apatite. Nevertheless, the mammary gland normally remains unmineralized and free of amyloid. Unlike κ-casein, β- and α_S-caseins are highly effective mineral chaperones that prevent ectopic and pathological calcification of the mammary gland. Milk invariably contains a mixture of two to five different caseins that act on each other as molecular chaperones. Instead of forming amyloid fibrils, several thousand caseins and hundreds of nanoclusters of amorphous calcium phosphate combine to form fuzzy complexes called casein micelles. To understand the biological functions of the casein micelle its structure needs to be understood better than at present. The location in micelles of the highly amyloidogenic κ-casein is disputed. In traditional hydrophobic colloid models, it, alone, forms a stabilizing surface coat that also determines the average size of the micelles. In the recent multivalent-binding model, κ-casein is present throughout the micelle, in intimate contact with the other caseins. To discriminate between these models, a range of biomimetic micelles was prepared using a fixed concentration of the mineral chaperone β-casein and nanoclusters of calcium phosphate, with variable concentrations of κ-casein. A biomimetic micelle was also prepared using a highly deuterated and <em>in vivo</em> phosphorylated recombinant β-casein with calcium phosphate and unlabelled κ-casein. Neutron and X-ray scattering experiments revealed that κ-casein is distributed throughout the micelle, in quantitative agreement with the multivalent-binding model but contrary to the hydrophobic colloid models.</p></div>","PeriodicalId":17238,"journal":{"name":"Journal of Structural Biology: X","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590152424000011/pdfft?md5=e8fc9848e4965cd95d0dfe026d8062cf&pid=1-s2.0-S2590152424000011-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139634123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Peptoid-based macrodiscs of variable lipid composition for structural studies of membrane proteins by oriented-sample solid-state NMR","authors":"Azamat R. Galiakhmetov,&nbsp;Adit A. Shah,&nbsp;Addison Lane,&nbsp;Carolynn M. Davern,&nbsp;Caroline Proulx,&nbsp;Alexander A. Nevzorov","doi":"10.1016/j.yjsbx.2023.100095","DOIUrl":"https://doi.org/10.1016/j.yjsbx.2023.100095","url":null,"abstract":"<div><p>Solid-state Nuclear Magnetic Resonance (NMR) in combination with magnetically aligned discoidal lipid mimics allows for studying the conformations of membrane proteins in planar, lipid-rich bilayer environments and at the physiological temperature. We have recently demonstrated the general applicability of macrodiscs composed of DMPC lipids and peptoid belts, which yield magnetic alignment and NMR spectroscopic resolution comparable or superior to detergent-containing bicelles. Here we report on a considerable improvement in the magnetic alignment and NMR resolution of peptoid-based macrodiscs consisting of a mixture of the zwitterionic and negatively charged lipids (DMPC/DMPG at the 85% to 15% molar ratio). The resulting linewidths are about 30% sharper due to the higher orientational order parameter likely arising from the stabilizing electrostatic repulsion between the discs. Moreover, highly aligned, detergent-free macrodiscs can be formed with a longer-chain lipid, DPPC. Interestingly, the spectra of Pf1 in the two lipid mimetics are almost indistinguishable, which would mean that the overall transmembrane helix tilt might be governed not only by the hydrophobic matching but also possibly by the interactions of the flanking lysine and arginine residues at the membrane interface.</p></div>","PeriodicalId":17238,"journal":{"name":"Journal of Structural Biology: X","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2590152423000119/pdfft?md5=facf5798311ccfe84d39976a2b84f0fc&pid=1-s2.0-S2590152423000119-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138549264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"NMR structure verifies the eponymous zinc finger domain of transcription factor ZNF750","authors":"Antonio J. Rua,&nbsp;Richard D. Whitehead 3rd,&nbsp;Andrei T. Alexandrescu","doi":"10.1016/j.yjsbx.2023.100093","DOIUrl":"10.1016/j.yjsbx.2023.100093","url":null,"abstract":"<div><p>ZNF750 is a nuclear transcription factor that activates skin differentiation and has tumor suppressor roles in several cancers. Unusually, ZNF750 has only a single zinc-finger (ZNF) domain, Z*, with an amino acid sequence that differs markedly from the CCHH family consensus. Because of its sequence differences Z* is classified as degenerate, presumed to have lost the ability to bind the zinc ion required for folding. AlphaFold predicts an irregular structure for Z* with low confidence. Low confidence predictions are often inferred to be intrinsically disordered regions of proteins, which would be the case if Z* did not bind Zn²⁺. We use NMR and CD spectroscopy to show that a 25–51 segment of ZNF750 corresponding to the Z* domain folds into a well-defined antiparallel ββα tertiary structure with a pM dissociation constant for Zn²⁺ and a thermal stability &gt;80 °C. Of three alternative Zn²⁺ ligand sets, Z* uses a CCHC rather than the expected CCHH ligating motif. The switch in the last ligand maintains the folding topology and hydrophobic core of the classical ZNF motif. CCHC ZNFs are typically associated with protein–protein interactions, raising the possibility that ZNF750 interacts with DNA through other proteins rather than directly. The structure of Z* provides context for understanding the function of the domain and its cancer-associated mutations. We expect other ZNFs currently classified as degenerate could be CCHC-type structures like Z*.</p></div>","PeriodicalId":17238,"journal":{"name":"Journal of Structural Biology: X","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2023-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ftp.ncbi.nlm.nih.gov/pub/pmc/oa_pdf/4d/b7/main.PMC10465944.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10231213","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cryo-EM of a heterogeneous biochemical fraction elucidates multiple protein complexes from a multicellular thermophilic eukaryote","authors":"Dmitry A. Semchonok ,&nbsp;Fotis L. Kyrilis ,&nbsp;Farzad Hamdi ,&nbsp;Panagiotis L. Kastritis","doi":"10.1016/j.yjsbx.2023.100094","DOIUrl":"10.1016/j.yjsbx.2023.100094","url":null,"abstract":"<div><p>Biomolecular complexes and their interactions govern cellular structure and function. Understanding their architecture is a prerequisite for dissecting the cell's inner workings, but their higher-order assembly is often transient and challenging for structural analysis. Here, we performed cryo-EM on a single, highly heterogeneous biochemical fraction derived from <em>Chaetomium thermophilum</em> cell extracts to visualize the biomolecular content of the multicellular eukaryote. After cryo-EM single-particle image processing, results showed that a simultaneous three-dimensional structural characterization of multiple chemically diverse biomacromolecules is feasible. Namely, the thermophilic, eukaryotic complexes of (a) ATP citrate-lyase, (b) Hsp90, (c) 20S proteasome, (d) Hsp60 and (e) UDP-glucose pyrophosphorylase were characterized. In total, all five complexes have been structurally dissected in a thermophilic eukaryote in a total imaged sample area of 190.64 μm², and two, in particular, 20S proteasome and Hsp60, exhibit side-chain resolution features. The <em>C. thermophilum</em> Hsp60 near-atomic model was resolved at 3.46 Å (FSC = 0.143) and shows a hinge-like conformational change of its equatorial domain, highly similar to the one previously shown for its bacterial orthologue, GroEL. This work demonstrates that cryo-EM of cell extracts will greatly accelerate the structural analysis of cellular complexes and provide unprecedented opportunities to annotate architectures of biomolecules in a holistic approach.</p></div>","PeriodicalId":17238,"journal":{"name":"Journal of Structural Biology: X","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2023-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10451023/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10107408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Discovery, characterization, and redesign of potent antimicrobial thanatin orthologs from Chinavia ubica and Murgantia histrionica targeting E. coli LptA","authors":"Kelly Huynh ,&nbsp;Amanuel Kibrom ,&nbsp;Bruce R. Donald ,&nbsp;Pei Zhou","doi":"10.1016/j.yjsbx.2023.100091","DOIUrl":"https://doi.org/10.1016/j.yjsbx.2023.100091","url":null,"abstract":"<div><p><em>Podisus maculiventris</em> thanatin has been reported as a potent antimicrobial peptide with antibacterial and antifungal activity. Its antibiotic activity has been most thoroughly characterized against <em>E. coli</em> and shown to interfere with multiple pathways, such as the lipopolysaccharide transport (LPT) pathway comprised of seven different Lpt proteins. Thanatin binds to <em>E. coli</em> LptA and LptD, thus disrupting the LPT complex formation and inhibiting cell wall synthesis and microbial growth. Here, we performed a genomic database search to uncover novel thanatin orthologs, characterized their binding to <em>E. coli</em> LptA using bio-layer interferometry, and assessed their antimicrobial activity against <em>E. coli</em>. We found that thanatins from <em>Chinavia ubica</em> and <em>Murgantia histrionica</em> bound tighter (by 3.6- and 2.2-fold respectively) to LptA and exhibited more potent antibiotic activity (by 2.1- and 2.8-fold respectively) than the canonical thanatin from <em>P. maculiventris</em>. We crystallized and determined the LptA-bound complex structures of thanatins from <em>C. ubica</em> (1.90 Å resolution), <em>M. histrionica</em> (1.80 Å resolution), and <em>P. maculiventris</em> (2.43 Å resolution) to better understand their mechanism of action. Our structural analysis revealed that residues A10 and I21 in <em>C. ubica</em> and <em>M. histrionica</em> thanatin are important for improving the binding interface with LptA, thus overall improving the potency of thanatin against <em>E. coli</em>. We also designed a stapled variant of thanatin that removes the need for a disulfide bond but retains the ability to bind LptA and antibiotic activity. Our discovery presents a library of novel thanatin sequences to serve as starting scaffolds for designing more potent antimicrobial therapeutics.</p></div>","PeriodicalId":17238,"journal":{"name":"Journal of Structural Biology: X","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2023-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49857582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Real-time tracking of drug binding to influenza A M2 reveals a high energy barrier","authors":"Kumar Tekwani Movellan,&nbsp;Melanie Wegstroth,&nbsp;Kerstin Overkamp,&nbsp;Andrei Leonov,&nbsp;Stefan Becker,&nbsp;Loren B. Andreas","doi":"10.1016/j.yjsbx.2023.100090","DOIUrl":"10.1016/j.yjsbx.2023.100090","url":null,"abstract":"<div><p>The drug Rimantadine binds to two different sites in the M2 protein from influenza A, a peripheral site and a pore site that is the primary site of efficacy. It remained enigmatic that pore binding did not occur in certain detergent micelles, and in particular incomplete binding was observed in a mixture of lipids selected to match the viral membrane. Here we show that two effects are responsible, namely changes in the protein upon pore binding that prevented detergent solubilization, and slow binding kinetics in the lipid samples. Using 55–100 kHz magic-angle spinning NMR, we characterize kinetics of drug binding in three different lipid environments: DPhPC, DPhPC with cholesterol and viral mimetic membrane lipid bilayers. Slow pharmacological binding kinetics allowed the characterization of spectral changes associated with non-specific binding to the protein periphery in the kinetically trapped pore-apo state. Resonance assignments were determined from a set of proton-detected 3D spectra. Chemical shift changes associated with functional binding in the pore of M2 were tracked in real time in order to estimate the activation energy. The binding kinetics are affected by pH and the lipid environment and in particular cholesterol. We found that the imidazole-imidazole hydrogen bond at residue histidine 37 is a stable feature of the protein across several lipid compositions. Pore binding breaks the imidazole-imidazole hydrogen bond and limits solubilization in DHPC detergent.</p></div>","PeriodicalId":17238,"journal":{"name":"Journal of Structural Biology: X","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2023-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10285276/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9772104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transformations between rotational and translational invariants formulated in reciprocal spaces","authors":"Philip R. Baldwin","doi":"10.1016/j.yjsbx.2023.100089","DOIUrl":"10.1016/j.yjsbx.2023.100089","url":null,"abstract":"<div><p>Correlation functions play an important role in the theoretical underpinnings of many disparate areas of the physical sciences: in particular, scattering theory. More recently, they have become useful in the classification of objects in areas such as computer vision and our area of cryoEM. Our primary classification scheme in the cryoEM image processing system, EMAN2, is now based on third order invariants formulated in Fourier space. This allows a factor of 8 speed up in the two classification procedures inherent in our software pipeline, because it allows for classification without the need for computationally costly alignment procedures.</p><p>In this work, we address several formal and practical aspects of such multispectral invariants. We show that we can formulate such invariants in the representation in which the original signal is most compact. We explicitly construct transformations between invariants in different orientations for arbitrary order of correlation functions and dimension. We demonstrate that third order invariants distinguish 2D mirrored patterns (unlike the radial power spectrum), which is a fundamental aspects of its classification efficacy. We show the limitations of 3rd order invariants also, by giving an example of a wide family of patterns with identical (vanishing) set of 3rd order invariants. For sufficiently rich patterns, the third order invariants should distinguish typical images, textures and patterns.</p></div>","PeriodicalId":17238,"journal":{"name":"Journal of Structural Biology: X","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10314203/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9802121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}