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Unraveling structure and performance of protein a ligands at liquid–solid interfaces: A multi-techniques analysis

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Chinese Journal of Chemical Engineering 2023年第2期54卷 232-239页

作者： Yi Shen Xinshuang chu Qinghong Shi Department of Biochemical Engineering School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300350China Key Laboratory of Systems Bioengineering and Frontiers Science Center for Synthetic Biology(Ministry of Education) Tianjin UniversityTianjin 300350China

Oriented ligand immobilization is one of the most effective strategies used in the design and construction of a high-capacity protein A chromatography. In this work, cysteine was introduced as anchoring sites by substituting a specific residue on Helix Ⅰ, Ⅱ, and at C-terminus of antibody binding domain Z from protein A, respectively, to investigate structural evolution and binding behavior of protein A ligands at liquid-solid interfaces. Among the three affinity dextran-coated Fe_(3)O_(4) magnetic nanoparticles(Fe_(3)O_(4)@Dx MNPs), affinity MNPs with the immobilized ligand via N11C on Helix Ⅰ(Fe_(3)O_(4)@Dx-Z_(1) MNPs) had the highest helical content, and MNPs with the immobilized ligand via G29C on Helix Ⅱ(Fe_(3)O_(4)@Dx-Z_(2) MNPs) had the lowest helical content at the same pHs. It was attributed to less electrostatic attraction of ligand to negatively charged surface on Fe_(3)O_(4)@Dx-Z_(1) MNPs because of less positive charged residues on Helix Ⅰ(K6) than Helix Ⅱ(R27/K35). Among the three affinity MNPs, moreover, the highest affinity to immunoglobulin G(IgG) binding was observed on Fe_(3)O_(4)@Dx-Z_(1) MNPs in isothermal titration calorimetry measurement, further validating greater structural integrity of the ligand on Fe_(3)O_(4)@Dx-Z_(1) MNPs. Finally,the study of IgG binding on MNPs and 96-well plates showed that anchoring sites for ligand immobilization had distinct influences on IgG binding and IgG-mediated antigen binding. This work illustrated that anchoring sites of the ligands had a striking significance for the molecular structure of the ligand at liquid-solid interfaces and raised an important implication for the design and optimization of protein A chromatography and protein A-based immunoassay analysis.

关键词： Adsorption Interface Thermodynamics Protein A ligand Immobilization Molecular structure

Coordinating gibberellin and brassinosteroid signaling beyond Green Revolution

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Journal of Genetics and Genomics 2023年第7期50卷 459-461页

作者： Hongning Tong Chengcai chu National Key Facility for Crop Gene Resources and Genetic Improvement Institute of Crop SciencesChinese Academy of Agricultural SciencesBeijing 100081China Guangdong Laboratory for Lingnan Modern Agriculture State Key Laboratory for Conservation and Utilization of Subtropical Agro-BioresourcesCollege of AgricultureSouth China Agricultural UniversityGuangzhouGuangdong 510642China

The Green Revolution,which took place in the 1960s,was instrumental in increasing grain yields and mitigating the world’s food *** semi-dwarfing crops was a critical activity that significantly improved lodging resistance,field management,and harvesting *** molecular genetic studies revealed that the semi-dwarfing genes used in rice and wheat,two major staple crops,are related to the plant hormone gibberellin(GA).In rice,SD1 encodes a defective GA synthetic enzyme GA20ox-2,while in wheat,Rht-1(Rht-B1b or Rht-D1b)encodes the gain-of-function form of the GA signaling inhibitors known as DELLA proteins(Peng et al.,1999;Sasaki et al.,2002).However,defects in either GA synthesis or signaling can decrease nitrogen use efficiency(NUE)and potentially lead to inferior grain ***,the success of the Green Revolution relies heavily on the massive input of nitrogen fertilizer,which causes severe environmental issues.

关键词： Wheat BR GA Green Revolution

Protein designer David Baker: I like doing things that seem like magic

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National Science Review 2020年第8期7卷 1410-1412页

作者： Weijie Zhao chu Wang NSR Peking University

Search ‘de novo protein design’ on Google and you will find the name David Baker in all results of the first page. Professor David Baker at the University of Washington and other scientists are opening up a new world of fantastic proteins. Protein is the direct executor of most biological functions and its structure and function are fully determined by its primary sequence. Baker’s group developed the Rosetta software suite that enabled the computational prediction and design of protein structures. Being able to design proteins from scratch means being able to design executors for diverse purposes and benefit society in multiple ways. Recently, NSR interviewed Prof. Baker on this fast-developing field and his personal experiences.

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[0001]-Oriented InN Nanoleaves and Nanowires: Synthesis,Growth Mechanism and Optical Properties

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Acta Metallurgica Sinica(English Letters) 2016年第9期29卷 820-826页

作者： Min Liu Hui-Qiang Liu Sheng chu Ru-Fang Peng Shi-Jin chu State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials Southwest University of Science and Technology State Key Laboratory of Optoelectronic Materials and Technology Sun Yat-Sen University

Novel indium nitride （INN） leaf-like nanosheets and nanowires have been grown on Si substrate by chemical vapor deposition method. The characterization results indicate that the samples are single-crystalline, and the growth direction of the nanowires and nanoleaves is [0001]. The growth mechanism of the InN nanoleaves is following the pattern of vapor-liquid-solid process with a three-step growth process. In addition, the room temperature photoluminescence spectra of two nanostructures show band-to-band emissions around 0.706 eV, where the emission from single nanoleaf is stronger than nanowire, showing potential for applications in optoelectronic devices.

关键词： Novel indium nitride (INN) Chemical vapor deposition (CVD) Nanoleaf Crystal structure Photoluminescence (PL)

The Effects of the Particle Size Ratio on the Behaviors of Binary Granular Materials

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Computer Modeling in Engineering & Sciences 2023年第7期136卷 63-85页

作者： Deze Yang Xihua chu School of Civil Engineering Wuhan UniversityWuhan430072China

The particle size ratio(PSR)is an important parameter for binary granular materials,which may aect the microstructure and macro behaviors of granular ***,the eect of particle ratio on granular assemblies with dierent arrangements is still *** explore and further clarify the eect of PSR in dierent packing structures,three types of numerical samples with regular,layered,and random packing are *** results show that PSR has signi􀀀cant eects on binary granular samples with regular *** larger the PSR,the stronger the strength,the larger the modulus,and the smaller the angle between the shear band and the load *** a theoretical solution of the peak stress ratio *** is obtained for regular packing,and the results by DEM are in good agreement with the theoretical *** layered packing,PSR has little eect on peak stress ratio due to similar microstructure obtained with the changing of *** modulus slightly increased with the increase of *** random packing with small grain content of 50%,PSR has little eect in the range of 0.5–0.9,but in a larger range,larger PSR leads to greater modulus.

关键词： Discrete element method binary granular materials particle size ratio packing

Chimeric antigen receptor engineered innate immune cells in cancer immunotherapy

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Science China(Life Sciences) 2019年第5期62卷 633-639页

作者： chu Lin Jun Zhang Department of Immunology School of Basic Medical Sciences NHC Key Laboratory of Medical Immunology (Peking University) Peking University Health Science Center

Introducing chimeric antigen receptor into immune cells against malignancies has contributed to a revolutionary innovation in cancer immunotherapy. As an important type of adaptive immune cells, T cells first caught researchers' attention and became great success in chimeric antigen receptor-based immunotherapy. However, engineered T cells seem to hit their bottleneck when resistance of cancerous cells, less encouraging responses in solid tumors and unwanted toxicities to the host remain to be ***, innate immune cells get to join the race. Representatives such as natural killer cells, natural killer T cells, γδT cells and macrophages also prove to be well redirected with chimeric antigen receptors. Compared to chimeric antigen receptor engineered T cells, these engineered innate immune cells may possess multiple targeting and killing mechanisms, have the potential to crack the barrier of solid tumors and have less side effects in the host. Besides, possible universal access to cell resources and improvements in expansion and transduction techniques make these cells promising candidates with huge potential in translational medicine. Therefore, innate immune cells claim a brand-new dimension and are likely to supplement T cells greatly in the field of chimeric antigen receptor-based immunotherapy.

关键词： chimeric antigen receptor cancer immunotherapy innate immune cell

Optimal regularity of plurisubharmonic envelopes on compact Hermitian manifolds

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Science China Mathematics 2019年第2期62卷 371-380页

作者： Jianchun chu Bin Zhou School of Mathematical Sciences Peking University

In this paper, we prove the C^(1,1)-regularity of the plurisubharmonic envelope of a C^(1,1) function on a compact Hermitian manifold. We also present the examples to show this regularity is sharp.

关键词： complex Monge-Ampère equations plurisubharmonic functions envelopes Hermitian manifolds

Achieving large transport bandgaps in bilayer graphene

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Nano Research 2015年第10期8卷 3228-3236页

作者： Tao chu Zhihong Chen SchoolofElectricalandComputerEngineeringandBirckNanotechnologyCenter PurdueUniversityWestLafayetteIN47907USA

Since opening sizable bandgaps in bilayer graphene （BLG） was proven possible, BLG has attracted considerable attention as a promising high-mobility candidate material for many electronic and optoelectronic applications. However, the bandgaps observed in the transport experiments reported in the literature are far smaller than both the theoretical predictions and the bandgaps extracted from optical measurements. In this study, we investigate the factors preventing the formation of large bandgaps and demonstrate that a -200-meV transport bandgap can be opened in BLG by scaling the gate dielectric and employing a ribbon channel to suppress the percolative transport. This is the largest transport bandgap that has been achieved in BLG to date.

关键词： bilayer graphene transport bandgap percolation on/off ratios

Finite Element Simulations on Failure Behaviors of Granular Materials with Microstructures Using a Micromechanics-Based Cosserat Elastoplastic Model

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Computer Modeling in Engineering & Sciences 2024年第3期138卷 2305-2338页

作者： Chenxi Xiu Xihua chu School of Civil Engineering Chongqing Jiaotong UniversityChongqing400074China School of Civil Engineering Wuhan UniversityWuhan430072China

This paper presents a micromechanics-based Cosserat continuum model for microstructured granular *** utilizing this model,the macroscopic constitutive parameters of granular materials with different microstructures are expressed as sums of microstructural *** microstructures under consideration can be classified into three categories:a medium-dense microstructure,a dense microstructure consisting of one-sized particles,and a dense microstructure consisting of two-sized ***,the Cosserat elastoplastic model,along with its finite element formulation,is derived using the extended Drucker-Prager yield *** investigate failure behaviors,numerical simulations of granular materials with different microstructures are conducted using the ABAQUS User Element(UEL)*** demonstrates the capacity of the proposed model to simulate the phenomena of strain-softening and strain *** study investigates the influence of microscopic parameters,including contact stiffness parameters and characteristic length,on the failure behaviors of granularmaterials ***,the study examines themesh independence of the presented model and establishes its relationship with the characteristic length.A comparison is made between finite element simulations and discrete element simulations for a medium-dense microstructure,revealing a good agreement in results during the elastic *** parameters describing plasticity are shown to be partially related to microscopic factors such as confining pressure and size of the representative volume element.

关键词： Granular materials micromechanics Cosserat elastoplastic model microstructures failure behaviors