Science
14 OCT 2022
Volume 378 | Issue 6616
Research
RESEARCH Articles
1. A bacterial phospholipid phosphatase inhibits host pyroptosis by hijacking ubiquitin 
下载原文
First Author:
Qiyao Chai①
Corresponding Authors:
Xiao-Bo Qiu②, Jing Wang③, Cui Hua Liu④
Affiliations:
CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.①③④
State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, Jiangsu, China. ②
Ministry of Education Key Laboratory of Cell Proliferation and Regulation Biology, College of Life Sciences, Beijing Normal University, Beijing 100875, China. ②
Savaid Medical School, University of Chinese Academy of Sciences, Beijing, China.④
Abstract:
The inflammasome-mediated cleavage of gasdermin D (GSDMD) causes pyroptosis and inflammatory cytokine release to control pathogen infection, but how pathogens evade this immune response remains largely unexplored. Here we identify the known protein phosphatase PtpB from Mycobacterium tuberculosis as a phospholipid phosphatase inhibiting the host inflammasome-pyroptosis pathway. Mechanistically, PtpB dephosphorylated phosphatidylinositol-4-monophosphate and phosphatidylinositol-(4,5)-bisphosphate in host cell membrane, thus disrupting the membrane localization of the cleaved GSDMD to inhibit cytokine release and pyroptosis of macrophages. Notably, this phosphatase activity requires PtpB binding to ubiquitin. Disrupting phospholipid phosphatase activity or the ubiquitin-interacting motif of PtpB enhanced host GSDMD-dependent immune responses and reduced intracellular pathogen survival. Thus, pathogens inhibit pyroptosis and counteract host immunity by altering host membrane composition.
2. Evolution of increased complexity and specificity at the dawn of form I Rubiscos 下载原文
First Author:
Luca Schulz①
Corresponding Authors:
Tobias J. Erb②. Georg K.A. Hochberg③
Affiliations:
Department of Biochemistry and Synthetic Metabolism, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.①②
Center for Synthetic Microbiology (SYNMIKRO), Philipps University Marburg, 35043 Marburg, Germany.②③
Evolutionary Biochemistry Group, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany.③
Abstract:
The evolution of ribulose-1,5-bisphosphate carboxylase/oxygenases (Rubiscos) that discriminate strongly between their substrate carbon dioxide and the undesired side substrate dioxygen was an important event for photosynthetic organisms adapting to an oxygenated environment. We use ancestral sequence reconstruction to recapitulate this event. We show that Rubisco increased its specificity and carboxylation efficiency through the gain of an accessory subunit before atmospheric oxygen was present. Using structural and biochemical approaches, we retrace how this subunit was gained and became essential. Our work illuminates the emergence of an adaptation to rising ambient oxygen levels, provides a template for investigating the function of interactions that have remained elusive because of their essentiality, and sheds light on the determinants of specificity in Rubisco.
3. Simultaneous electrical and thermal rectification in a monolayer lateral heterojunction 下载原文
First Author:
Yufeng Zhang①
Corresponding Authors:
Haidong Wang②, Ruitao Lv③,Xing Zhang④
Affiliations:
Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China.①②④
State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China.③
Key Laboratory of Advanced Materials (Ministry of Education), School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China.③
Abstract:
Efficient waste heat dissipation has become increasingly challenging as transistor size has decreased to nanometers. As governed by universal Umklapp phonon scattering, the thermal conductivity of semiconductors decreases at higher temperatures and causes heat transfer deterioration under high-power conditions. In this study, we realized simultaneous electrical and thermal rectification (TR) in a monolayer MoSe2-WSe2 lateral heterostructure. The atomically thin MoSe2-WSe2 heterojunction forms an electrical diode with a high ON/OFF ratio up to 104. Meanwhile, a preferred heat dissipation channel was formed from MoSe2 to WSe2 in the ON state of the heterojunction diode at high bias voltage with a TR factor as high as 96%. Higher thermal conductivity was achieved at higher temperatures owing to the TR effect caused by the local temperature gradient. Furthermore, the TR factor could be regulated from maximum to zero by rotating the angle of the monolayer heterojunction interface. This result opens a path for designing novel nanoelectronic devices with enhanced thermal dissipation.
4. Covalent organic framework–based porous ionomers for high-performance fuel cells 下载原文
First Author:
Qingnuan Zhang①
Corresponding Authors:
Xiao Feng②, Bo Wang③
Affiliations:
Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion Materials, Key Laboratory of Cluster Science, Ministry of Education, Frontiers Science Center for High Energy Material, Advanced Technology Research Institute (Jinan), School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, P. R. China. ①②③
Abstract: Lowering platinum (Pt) loadings without sacrificing power density and durability in fuel cells is highly desired yet challenging because of the high mass transport resistance near the catalyst surfaces. We tailored the three-phase microenvironment by optimizing the ionomer by incorporating ionic covalent organic framework (COF) nanosheets into Nafion. The mesoporous apertures of 2.8 to 4.1 nanometers and appendant sulfonate groups enabled the proton transfer and promoted oxygen permeation. The mass activity of Pt and the peak power density of the fuel cell with Pt/Vulcan (0.07 mg of Pt per square centimeter in the cathode) both reached 1.6 times those values without the COF. This strategy was applied to catalyst layers with various Pt loadings and different commercial catalysts.
5. Real-time dynamic single-molecule protein sequencing on an integrated semiconductor device 下载原文
First Author/Corresponding Author:
Brain D. Reed
Affiliation：
Quantum-Si, Inc., Guilford, CT 06437, USA.
Abstract:
Studies of the proteome would benefit greatly from methods to directly sequence and digitally quantify proteins and detect posttranslational modifications with single-molecule sensitivity. Here, we demonstrate single-molecule protein sequencing using a dynamic approach in which single peptides are probed in real time by a mixture of dye-labeled N-terminal amino acid recognizers and simultaneously cleaved by aminopeptidases. We annotate amino acids and identify the peptide sequence by measuring fluorescence intensity, lifetime, and binding kinetics on an integrated semiconductor chip. Our results demonstrate the kinetic principles that allow recognizers to identify multiple amino acids in an information-rich manner that enables discrimination of single amino acid substitutions and posttranslational modifications. With further development, we anticipate that this approach will offer a sensitive, scalable, and accessible platform for single-molecule proteomic studies and applications.
REPORTS
6. Direct identification of the charge state in a single platinum nanoparticle on titanium oxide 下载原文
First Author:
Ryotaro Aso①
Corresponding Author:
Yasukazu Murakami②
Affiliations:
Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan.①
The Ultramicroscopy Research Center, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan.②
Abstract:
A goal in the characterization of supported metal catalysts is to achieve particle-by-particle analysis of the charge state strongly correlated with the catalytic activity. Here, we demonstrate the direct identification of the charge state of individual platinum nanoparticles (NPs) supported on titanium dioxide using ultrahigh sensitivity and precision electron holography. Sophisticated phase-shift analysis for the part of the NPs protruding into the vacuum visualized slight potential changes around individual platinum NPs. The analysis revealed the number (only one to six electrons) and sense (positive or negative) of the charge per platinum NP. The underlying mechanism of platinum charging is explained by the work function differences between platinum and titanium dioxide (depending on the orientation relationship and lattice distortion) and by first-principles calculations in terms of the charge transfer processes.
7. Mixed plastics waste valorization through tandem chemical oxidation and biological funneling 下载原文
First Author:
Kevin P. Sullivan ①
Corresponding Authors:
Shannon S. Stahl.②, Gregg T.Beckham③
Affiliations:
Renewable Resources and Enabling Sciences Center, National
Renewable Energy Laboratory, Golden, CO, USA.①③
BOTTLE Consortium, Golden, CO, USA.①③
Department of Chemistry, University of Wisconsin Madison, Madison, WI, USA.②
Abstract:
Mixed plastics waste represents an abundant and largely untapped feedstock for the production of valuable products. The chemical diversity and complexity of these materials, however, present major barriers to realizing this opportunity. In this work, we show that metal-catalyzed autoxidation depolymerizes comingled polymers into a mixture of oxygenated small molecules that are advantaged substrates for biological conversion. We engineer a robust soil bacterium, Pseudomonas putida, to funnel these oxygenated compounds into a single exemplary chemical product, either β-ketoadipate or polyhydroxyalkanoates. This hybrid process establishes a strategy for the selective conversion of mixed plastics waste into useful chemical products.
8.Polymeric multimaterials by photochemical patterning of crystallinity 下载原文
First Author:
Henry L. Cater①
Corresponding Author:
Zachariah A. Page②
Affiliation:
Department of Chemistry, The University of Texas at Austin, Austin, TX 78712, USA.
Abstract:
An organized combination of stiff and elastic domains within a single material can synergistically tailor bulk mechanical properties. However, synthetic methods to achieve such sophisticated architectures remain elusive. We report a rapid, facile, and environmentally benign method to pattern strong and stiff semicrystalline phases within soft and elastic matrices using stereo-controlled ring-opening metathesis polymerization of an industrial monomer, cis-cyclooctene. Dual polymerization catalysis dictates polyolefin backbone chemistry, which enables patterning of compositionally uniform materials with seamless stiff and elastic interfaces. Visible light–induced activation of a metathesis catalyst results in the formation of semicrystalline trans polyoctenamer rubber, outcompeting the formation of cis polyoctenamer rubber, which occurs at room temperature. This bottom-up approach provides a method for manufacturing polymeric materials with promising applications in soft optoelectronics and robotics.