Research Progress----Shanghai Advanced Research Institute,Chinese Academy of Sciences

Researchers Reveal Sau3AI Represents a New Subclass of Type IIE Restriction Enzymes by Studying its Crystal Structure

Recently, a research team led by Prof. YU Feng at Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences and Prof. HE Jianhua at Wuhan University reported a self-activating mechanism that the Sau3AI C-terminal domain opens the N-terminal catalytic domain through allosteric effects to achieve cleavage of DNA-specific sites.The research results were published in the Structure on August. 30th.

　　Sau3AI is a type II restriction enzyme widely used for genetic manipulation, such as genome library construction. Sau3AI consists of two domains, the N-terminal domain (Sau3AI-N) and the C-terminal domain (Sau3AI-C). How these two domains work together to cut DNA remains unclear.
　　Recently, a research team led by Prof. YU Feng at Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences and Prof. HE Jianhua at Wuhan University reported a self-activating mechanism in which the Sau3AI C-terminal domain opens the N-terminal catalytic domain through allosteric effects to achieve cleavage of DNA-specific sites.
　　The results were published in Structure on Aug. 30.
　　As DNA cleavage activity, Sau3AI cannot be expressed in Escherichia coli, a catalytic site mutant, Sau3AI-E64A, was used for exogenous expression and structural research. The crystal structure of the Sau3AI-E64A mutant reveals that when DNA is not bound, a loop region (333-342) of the C-terminal domain hangs over DNA binding site of N-terminal domain, preventing N-terminal domain from binding to DNA.
　　Analysis of the Sau3AI C-terminal domain and DNA complex structure revealed that the loop region (261-268 and 280-295) of C-terminal domain was significantly altered after binding to DNA, implying that Sau3AI may undergo conformational changes after C-terminal domain binds to DNA. Further gel shift assay was performed on the DNA binding key amino acid residue mutants (K257A, S424A, and T435A) in C-terminal domain to confirm that C-terminal binding DNA plays a crucial role in activating the catalytic activity of N-terminal domain. These results suggest that C-terminal domain activates the enzymatic activity of N-terminal domain through allosteric effects.
　　The researchers suggested that Sau3AI is a type IIE restriction enzyme, but unlike other type IIE restriction enzymes, Sau3AI is monomeric rather than homodimer. This study demonstrates that two different domains in Sau3AI play a similar role to homodimers in other type IIE restriction enzymes, suggesting that Sau3AI represents a new subclass of type IIE restriction enzymes.
　　The structure of Sau3AI C-terminal and DNA complex (image by SARI)
　　

2023-08-28 more+

Researchers Develop Target Therapy of Buried Interface for Highly Efficient Perovskite Solar Cells

A research team at Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences, collaborated with researchers from the Southern University of Science and Technology and the City University of Hong Kong, reported a facile and effective strategy that is employed for precisely modulating the buried interface through the incorporation of formamidine oxalate (FOA) in a colloidal SnO2-based ETL.The research results were published in the Advanced Materials on July. 17th.

Perovskite solar cells (PSCs) have become a revolutionary photovoltaic technology, which endows the photovoltaic market with strong competitiveness due to their advantages of high performance, low cost, and easy fabrication of large-scale flexible devices.
　　SnO2 is a commonly used electron transport material for n-i-p PSCs due to its high light transmittance and electron mobility, suitable energy levels, good stability under UV irradiation, and can be processed at low temperatures. The buried interface of perovskite/SnO2 plays a crucial role in achieving high efficiency and stability. However, the non-exposed buried interface is challenging to study and manipulate.
　　Motivated by such a challenge, Dr. JI Xiaofei, the assistant researcher in LU Linfeng team at Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences, collaborated with researchers from the Southern University of Science and Technology and the City University of Hong Kong, reported a facile and effective strategy that is employed for precisely modulating the buried interface through the incorporation of formamidine oxalate (FOA) in a colloidal SnO2-based ETL.
　　The research results were published in the Advanced Materials on July. 17th.
　　According to research findings, both formamidinium (FA+) and oxalate ions show a longitudinal gradient distribution in the SnO2 layer, and mostly accumulating at the SnO2/perovskite buried interface. The modified SnO2 exhibits higher Fermi level, which induces the better energy level alignment between perovskite and SnO2-FOA, and helps avoid carrier accumulation at the interface and improves open-circuit voltage.
　　Moreover, the FOA can also modulate the crystal growth of upper perovskite films, which enables high-quality perovskite films with minimized grain boundaries and superior interface contacts.
　　Significantly, FA+ cations and oxalate anions can suppress the VO and Sni defects on the SnO2 surface and the FA+/Pb2+ associated defects at the perovskite buried interface contemporaneously, which contribute to achieve target defect passivation. Ultimately, the FOA-modified buried interface significantly increases the champion PCE to 25.05% with enhanced stability of corresponding devices under light, heat, and moisture conditions.
　　The study provides an in-depth understanding of the perovskite buried interface and an effective target therapy to improve the optoelectronic properties of PSCs.
　　The schematic diagram of modulating interfacial energy level, regulating perovskite crystal growth, and reducing interfacial defects for FOA (Image by SARI)
　　

2023-07-27 more+

Researchers Construct Post-synthetic Modification of Covalent Organic Frameworks for CO2 Electroreduction

A research team at the Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences constructed a multilevel post-synthetic modification strategy to construct catalytic COFs towards CO2RR with high activity and selectivity. The research results were published in Nature Communications.

Covalent organic frameworks (COFs), which possess ordered pores and high-precision functionalization, are regarded as an ideal class of templates to construct catalysts for electrocatalytic carbon dioxide reduction reaction (CO2RR).
　　The C-N bonds can improve the adsorption of CO2 and ionic skeletons can promote the charge transfer, further enhancing the conductivity. However, directly bottom-up synthesis can hardly realize the co-existence of C-N bonds and ionic frameworks due to the electrostatic repulsion and weak strength of the linkage.
　　Motivated by this challenge, a research team led by Prof. ZENG Gaofeng and Associate Prof. XU Qing at the Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences constructed a multilevel post-synthetic modification strategy to construct catalytic COFs towards CO2RR with high activity and selectivity. The research results were published in Nature Communications.
　　The catalytic COFs synthesised by the post modification show a maximum turnover frequencie value of 9922.68 h–1 at –1.0 V and the highest faradaic efficiencies of 97.32% at –0.8 V, which are higher than that of the base COF and the single-modified COFs. The electrocatalysis tests and characterizations reveal that C-N bonds can improve the catalytic selectivity and ionic skeleton contributes to higher activity.
　　Furthermore, the theoretical calculations illustrate that the easier formation of immediate *CO from COOH* is the rate determined step, and methyl groups strengthen the electron density.
　　This work provides a deeper understanding of COFs in CO2 reduction reaction. In the meantime, it sheds light on constructing multilevel post-synthetic modification COFs towards tailored activity and high stability.
　　
　　Catalytic covalent organic frameworks with bifunctional roles in oxygen reduction reaction (from O2 to H2O) and oxygen evolution reaction (from H2O to O2) have been first demonstrated by integrating redox-active sites into the Co-porphyrin frameworks. (Image by SARI)
　　

2023-06-29 more+

Scientists Develop a Novel Approach to Support Future Power System

Large-scale clusters of electric vehicles (EVs) are an important reserve measure supporting the construction of new power system. Key technologies towards the reliable and economic operation require collaborative innovation across disciplines and fields.Driven by the increasing needs, a joint research team led by Shanghai Advanced Research Institute of the Chinese Academy of Sciences proposed a novel approach to support future power system towards global net-zero emission target. The results were published in the latest issue of Renewable and Sustainable Energy Reviews.

　　The fundamental solution to achieve the "double carbon" goal is to transform the traditional energy consumption toward a low-carbon environment. Therefore, building a new type of power system with new energy sources can guarantee the low-carbon transformation of energy.
　　Large-scale clusters of electric vehicles (EVs) are an important reserve measure supporting the construction of new power system. Key technologies towards the reliable and economic operation require collaborative innovation across disciplines and fields.
　　Driven by the increasing needs, a joint research team led by Shanghai Advanced Research Institute of the Chinese Academy of Sciences and Nanjing University of Posts and Telecommunications proposed a novel multidisciplinary approach to support future power system towards global net-zero emission target.
　　The results were published in the latest issue of Renewable and Sustainable Energy Reviews.
　　This research group reconciled large-scale electric vehicle clusters into the power grid as a case study, and proposed the framework of interactions with physical flow, behavioral flow and information flow.
　　They first analyzed the physical characteristics of electric vehicle clusters providing power system reserve from the perspectives of performance characteristics, resource aggregation, scheduling strategies, and market mechanisms.
　　Then, the importance of social factors was emphasized and a hybrid simulation technology that integrates human participants and computer multi-agents was proposed, to solve the problem of heterogeneity in users’ decision-marking behavior.
　　In addition, the research group discussed the potential solutions regarding global communication coverage, frequency band interference and avoidance, communication security, and customized priority protection. Based on the perspective of the integration of public/private communication networks with Chinese characteristics, the researchers contrapuntally proposed grant-free transmission strategy, joint differentiated spectrum sensing & frequency hopping scheme, and implicit dimension labeling technique for the challenges above.
　　The research work provides technical support and feasible directions for multiple types of distributed reserve resources such as large scientific installations, office buildings, and industrial and agricultural production loads, which can enhance the flexible regulation capability of future power systems. It also introduces a feasibility guarantee that enables more distributed reserve resources for future power systems in various countries and regions.
　　An illustration of full-domain application of the new electric power system (Image by SARI)
　　

2023-06-21 more+

Novel Approach towards the Fabrication of Artificial GNRs with Pentagon Carbon Embedded

a research team led by Prof. SONG Fei at Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences reported a novel approach to precisely fabricate well-defined GNRs with the tailored carbon pentagon embedded inside, supported on the Ag(111) model catalyst. The results were published in Journal of Physical Chemistry Letters entitled "On-Surface Synthesis of Pentagon-Incorporated Graphene-Like Nanoribbons with Multiple Precursors”.

2023-06-16 more+

Researchers Develop Highly Efficient Ampere-Level CO2 Reduction to Multicarbon Products via Stepwise Hollow-Fiber Penetration Electrodes

Recent studies have shown that serial hollow-fiber penetration electrodes (HPEs) can improve the CO2ERR performance significantly. To promote the selectivity and current density for C2+ products simultaneously, a research team from the Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences developed a stepwise CO2ERR strategy using Ag and Cu HPEs to reach high-rate C2+ production.The results were published in Appl. Catal. B-Environ. on 28th May, 2023.

　　Though efficient C2+ production from CO2 electrocatalytic reduction reaction (CO2ERR) has become a promising approach to mitigate CO2 emissions and store intermittent renewable energy, it suffers from low selectivity and undesired side reactions.
　　Recent studies have shown that serial hollow-fiber penetration electrodes (HPEs) can improve the CO2ERR performance significantly by forcing CO2 to disperse and penetrate through the abundant pores on HPE wall, which greatly boosted CO2ERR kinetics.
　　To promote the selectivity and current density for C2+ products simultaneously, a research team led by Profs. CHEN Wei and WEI Wei from the Shanghai Advanced Research Institute (SARI) of the Chinese Academy of Sciences developed a stepwise CO2ERR strategy using Ag and Cu HPEs to reach high-rate C2+ production.
　　The results were published in Appl. Catal. B-Environ. on 28th May, 2023.
　　Specifically, for stepwise CO2 electroreduction, CO2 was firstly reduced into CO over a chloride ion regulated Ag hollow-fiber penetration electrodes with a 3.2 A？cm-2 partial current density and a 90.3% faradaic efficiency of CO. Then, a chloride ion regulated Cu hollow-fiber penetration further converted CO into C2+ products with a 1.8 A cm-2 partial current density and a 90.5% faradaic efficiency of C2+ products. Both steps were steadily conducted under total current density of 2 A？cm-2 for 200 hours.
　　Experimental results and density functional theory calculations show that synergetic combination of the unique penetration effect and the regulated electronic structures resulted in the superior performance toward C2+ production
　　This work shed light on designing electrocatalytic systems with exceedingly efficient CO2 electroreduction of high current density and selectivity as well as good durability, which might contribute to the scalable CO2 electroreduction applications towards high-value C2+ chemicals.
　　Schematic diagram for highly efficient ampere-level CO2 reduction to multicarbon products via stepwise hollow-fiber penetration electrodes (Image by SARI)
　　

2023-06-05 more+