Rationally Tuning the Active Sites of Copper-Based Catalysts towards Formaldehyde Reforming into Hydrogen

2021 ◽  
Author(s):  
Shuang Chen ◽  
Xueyan Pan ◽  
Leilei Du ◽  
Xiaoqing Yan ◽  
Sha Li ◽  
...  
Keyword(s):  
Active Sites ◽  
Large Scale ◽  
Reliable Method ◽  
Organic Fuels

Direct splitting of liquid organic fuels using a particulate catalyst is an effective way to produce hydrogen on a large scale. Here, we report a simple and reliable method for...

scholarly journals Coupled structural transitions enable highly cooperative regulation of human CTPS2 filaments

2019 ◽  
Author(s):  
Eric M. Lynch ◽  
Justin M. Kollman
Keyword(s):  
Enzyme Activity ◽  
Active Sites ◽  
Large Scale ◽  
Conformational State ◽  
Ctp Synthase ◽  
Widespread Phenomenon ◽  
And Control ◽  
Allosteric Regulators ◽  
Low Activity

Many enzymes assemble into defined oligomers, providing a mechanism for cooperatively regulating enzyme activity. Recent studies in tissues, cells, and in vitro have described a mode of regulation in which enzyme activity is modulated by polymerization into large-scale filaments1–5. Enzyme polymerization is often driven by binding to substrates, products, or allosteric regulators, and tunes enzyme activity by locking the enzyme in high or low activity states1–5. Here, we describe a unique, ultrasensitive form of polymerization-based regulation employed by human CTP synthase 2 (CTPS2). High-resolution cryoEM structures of active and inhibited CTPS2 filaments reveal the molecular basis of this regulation. Rather than selectively stabilizing a single conformational state, CTPS2 filaments dynamically switch between active and inactive filament forms in response to changes in substrate and product levels. Linking the conformational state of many CTPS2 subunits in a filament results in highly cooperative regulation, greatly exceeding the limits of cooperativity for the CTPS2 tetramer alone. The structures also reveal a link between conformational state and control of ammonia channeling between the enzyme’s two active sites. This filament-based mechanism of enhanced cooperativity demonstrates how the widespread phenomenon of enzyme polymerization can be adapted to achieve different regulatory outcomes.

scholarly journals New Insights about Enzyme Evolution from Large Scale Studies of Sequence and Structure Relationships

2014 ◽  
Vol 289 (44) ◽  
pp. 30221-30228 ◽  
Author(s):  
Shoshana D. Brown ◽  
Patricia C. Babbitt
Keyword(s):  
Structure Function ◽  
Active Sites ◽  
Large Scale ◽  
Common Ancestor ◽  
Enzyme Evolution ◽  
Large Set ◽  
Substrate Specificities ◽  
Functionally Diverse

Understanding how enzymes have evolved offers clues about their structure-function relationships and mechanisms. Here, we describe evolution of functionally diverse enzyme superfamilies, each representing a large set of sequences that evolved from a common ancestor and that retain conserved features of their structures and active sites. Using several examples, we describe the different structural strategies nature has used to evolve new reaction and substrate specificities in each unique superfamily. The results provide insight about enzyme evolution that is not easily obtained from studies of one or only a few enzymes.

scholarly journals Atomically dispersed nickel as coke-resistant active sites for methane dry reforming

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Mohcin Akri ◽  
Shu Zhao ◽  
Xiaoyu Li ◽  
Ketao Zang ◽  
Adam F. Lee ◽  
...  
Keyword(s):  
Active Sites ◽  
Large Scale ◽  
Low Cost ◽  
Coke Formation ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Highly Active ◽  
Catalytic Sites ◽  
Earth Abundant ◽  
Poor Stability

AbstractDry reforming of methane (DRM) is an attractive route to utilize CO2 as a chemical feedstock with which to convert CH4 into valuable syngas and simultaneously mitigate both greenhouse gases. Ni-based DRM catalysts are promising due to their high activity and low cost, but suffer from poor stability due to coke formation which has hindered their commercialization. Herein, we report that atomically dispersed Ni single atoms, stabilized by interaction with Ce-doped hydroxyapatite, are highly active and coke-resistant catalytic sites for DRM. Experimental and computational studies reveal that isolated Ni atoms are intrinsically coke-resistant due to their unique ability to only activate the first C-H bond in CH4, thus avoiding methane deep decomposition into carbon. This discovery offers new opportunities to develop large-scale DRM processes using earth abundant catalysts.

scholarly journals Nitrogen-Doped Porous Co3O4/Graphene Nanocomposite for Advanced Lithium-Ion Batteries

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1253 ◽  
Author(s):  
Huihui Zeng ◽  
Baolin Xing ◽  
Lunjian Chen ◽  
Guiyun Yi ◽  
Guangxu Huang ◽  
...  
Keyword(s):  
Lithium Ion Batteries ◽  
Anode Material ◽  
Self Assembly ◽  
Active Sites ◽  
Large Scale ◽  
Lithium Ion ◽  
Reversible Capacity ◽  
Co3o4 Nanoparticles ◽  
Nitrogen Doped ◽  
Novel Approach

A novel approach is developed to synthesize a nitrogen-doped porous Co3O4/anthracite-derived graphene (Co3O4/AG) nanocomposite through a combined self-assembly and heat treatment process using resource-rich anthracite as a carbonaceous precursor. The nanocomposite contains uniformly distributed Co3O4 nanoparticles with a size smaller than 8 nm on the surface of porous graphene, and exhibits a specific surface area (120 m2·g−1), well-developed mesopores distributed at 3~10 nm, and a high level of nitrogen doping (5.4 at. %). These unique microstructure features of the nanocomposite can offer extra active sites and efficient pathways during the electrochemical reaction, which are conducive to improvement of the electrochemical performance for the anode material. The Co3O4/AG electrode possesses a high reversible capacity of 845 mAh·g−1 and an excellent rate capacity of 587 mAh·g−1. Furthermore, a good cyclic stability of 510 mAh·g−1 after 100 cycles at 500 mA·g−1 is maintained. Therefore, this work could provide an economical and effective route for the large-scale application of a Co3O4/AG nanocomposite as an excellent anode material in lithium-ion batteries.

scholarly journals Engineering active sites on hierarchical transition bimetal oxides/sulfides heterostructure array enabling robust overall water splitting

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Panlong Zhai ◽  
Yanxue Zhang ◽  
Yunzhen Wu ◽  
Junfeng Gao ◽  
Bo Zhang ◽  
...  
Keyword(s):  
Water Splitting ◽  
Active Sites ◽  
Rational Design ◽  
Large Scale ◽  
Grand Challenge ◽  
Long Term Stability ◽  
Large Current ◽  
Electrode Cell ◽  
Large Current Density ◽  
Current Densities

Abstract Rational design of the catalysts is impressive for sustainable energy conversion. However, there is a grand challenge to engineer active sites at the interface. Herein, hierarchical transition bimetal oxides/sulfides heterostructure arrays interacting two-dimensional MoOx/MoS2 nanosheets attached to one-dimensional NiOx/Ni3S2 nanorods were fabricated by oxidation/hydrogenation-induced surface reconfiguration strategy. The NiMoOx/NiMoS heterostructure array exhibits the overpotentials of 38 mV for hydrogen evolution and 186 mV for oxygen evolution at 10 mA cm−2, even surviving at a large current density of 500 mA cm−2 with long-term stability. Due to optimized adsorption energies and accelerated water splitting kinetics by theory calculations, the assembled two-electrode cell delivers the industrially relevant current densities of 500 and 1000 mA cm−2 at record low cell voltages of 1.60 and 1.66 V with excellent durability. This research provides a promising avenue to enhance the electrocatalytic performance of the catalysts by engineering interfacial active sites toward large-scale water splitting.

Bioinspired Growth of Hydroxyapatite Nanocrystals on PLGA- (PEG- ASP)n Scaffolds Modified with Oligopeptide Derived from BMP-2

2007 ◽  
Vol 334-335 ◽  
pp. 1261-1264 ◽  
Author(s):  
Quan Yuan ◽  
Xiao Dong Guo ◽  
Qi Xin Zheng ◽  
Ming Zhao ◽  
Zheng Qi Pan ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Active Sites ◽  
Large Scale ◽  
Organic Matrix ◽  
Sem Analysis ◽  
Bone Morphogenetic Protein 2 ◽  
Intimate Contact ◽  
Simple Method ◽  
Natural Bone

Natural bone is a typical example of an “organic matrix-mediated” biomineralization process which constituted of hydroxyapatite(HA) nanocrystals orderly grown in intimate contact with collagen fibers. Bone morphogenetic protein 2 (BMP2) is the most powerful osteogenic factor. But it is extremely difficult to be manufactured in large scale. In previous study, we have designed a novel oligopeptide (P24) derived from BMP2 knuckle epitope and it contained abundant Asp(aspartic acid) and phosphorylated Ser(serine) which may be helpful for self-assambly biomineralization and osteogenesis. Previous In vivo experiments have shown that this novel oligopeptide had excellent osteoinductive and ectopic bone formation property which was similar to that of BMP2. In this study, PLGA-(PEG-ASP)n scaffolds were modified with P24 and a new biomimetic bone tissue engineering scaffold material with enhanced bioactivity was synthesized by a biologically inspired mineralization approach. Peptide P24 was introduced into PLGA-(PEG-ASP)n scaffolds using cross-linkers. Then the P24 modified scaffolds and the simple PLGA-(PEG-ASP)n scaffolds were incubated in modified simulated body fluid (mSBF) for 10 days. Growth of HA nanocrystals on the materials was confirmed by observation SEM and measurements EDS and XRD. SEM analysis demonstrated the well growth of bonelike HA nanocrystals on P24 modified PLGA-(PEG-ASP)n scaffolds than that of the control scaffolds. The main component of mineral of the P24 modified scaffolds was hydroxyapatite containing low crystalline nanocrystals, and the Ca/P ratio was nearly 1.60, similar to that of natural bone, while that of the control scaffolds was 1.52. The introduction of peptide P24 into PLGA- (PEG- ASP)n copolymer provides abundant active sites to mediate the nucleation and self- ssembling of HA nanocrystals in mSBF. the resulted peptide P24 modified- HA/PLGA- (PEG- ASP)n composite shows some features of natural bone both in main composition and and hierarchical microstructure. This biomimetic treatment provides a simple method for surface functionalization and subsequent biomineralization on biodegradable polymer scaffolds for tissue engineering.

scholarly journals Development of In2O3-based Catalysts for CO2-based Methanol Production

2020 ◽  
Vol 74 (4) ◽  
pp. 257-262 ◽  
Author(s):  
Matthias S. Frei ◽  
Cecilia Mondelli ◽  
Javier Pérez-Ramírez
Keyword(s):  
Life Cycle Analysis ◽  
Active Sites ◽  
Large Scale ◽  
Atomic Level ◽  
Minimal Amount ◽  
Monoclinic Zirconia ◽  
Planetary Boundaries ◽  
Hydrogen Activation ◽  
Catalytic Systems ◽  
Methanol Production

CO2 valorization into chemicals and fuels is a key area in current academic and industrial research, with thermocatalytic hydrogenation to methanol comprising one of the most advanced routes. Life-cycle analysis coupled to the framework of planetary boundaries has recently confirmed the sustainability of this process in absolute terms, emphasizing the need for cheaper CO2 and renewable H2 and for a catalytic system embracing high activity, selectivity, and durability to meet economic requirements. Herein, our research efforts aimed to gather atomic-level understanding of electronic and geometric properties of active sites in breakthrough In2O3-based catalytic systems guiding their development are reviewed. In-depth mechanistic elucidations identified limited hydrogen activation ability as well as water-driven sintering as limitations of pure In2O3. The former aspect was successfully addressed by adding through coprecipitation a minimal amount of palladium, forming tiny clusters strongly anchored to the oxide lattice leading to an unprecedented sustained methanol productivity. The use of monoclinic zirconia as a carrier, enabling high In2O3 dispersion in two-dimensional nanostructures, inducing the formation of additional active sites on In2O3, and contributing to CO2 activation, offered an efficient way to further boost activity and tackle In2O3 sintering. Overall, our findings set solid grounds to rationally design a supported and promoted In2O3 catalyst holding bright prospects for use at a large scale.

RECOGNIZING COMPLEX, ASYMMETRIC FUNCTIONAL SITES IN PROTEIN STRUCTURES USING A BAYESIAN SCORING FUNCTION

2003 ◽  
Vol 01 (01) ◽  
pp. 119-138 ◽  
Author(s):  
LIPING WEI ◽  
RUSS B. ALTMAN
Keyword(s):  
Binding Sites ◽  
Calcium Binding ◽  
Active Sites ◽  
Large Scale ◽  
Protein Structures ◽  
Scoring Function ◽  
Chemical Properties ◽  
Data Bank ◽  
Functional Sites ◽  
Calcium Binding Sites

The increase in known three-dimensional protein structures enables us to build statistical profiles of important functional sites in protein molecules. These profiles can then be used to recognize sites in large-scale automated annotations of new protein structures. We report an improved FEATURE system which recognizes functional sites in protein structures. FEATURE defines multi-level physico-chemical properties and recognizes sites based on the spatial distribution of these properties in the sites' microenvironments. It uses a Bayesian scoring function to compare a query region with the statistical profile built from known examples of sites and control nonsites. We have previously shown that FEATURE can accurately recognize calcium-binding sites and have reported interesting results scanning for calcium-binding sites in the entire Protein Data Bank. Here we report the ability of the improved FEATURE to characterize and recognize geometrically complex and asymmetric sites such as ATP-binding sites and disulfide bond-forming sites. FEATURE does not rely on conserved residues or conserved residue geometry of the sites. We also demonstrate that, in the absence of a statistical profile of the sites, FEATURE can use an artificially constructed profile based on a priori knowledge to recognize the sites in new structures, using redoxin active sites as an example.

scholarly journals A Multi-Pronged Approach Targeting SARS-CoV-2 Proteins Using Ultra-Large Virtual Screening

2020 ◽  
Author(s):  
Christoph Gorgulla ◽  
Krishna PadmanabhaDas ◽  
Kendra E. Leigh ◽  
Marco Cespugli ◽  
Patrick D. Fischer ◽  
...  
Keyword(s):  
Virtual Screening ◽  
In Silico ◽  
Active Sites ◽  
Large Scale ◽  
Protein Protein Interaction ◽  
The Face ◽  
Computing Platforms ◽  
Screening Platform ◽  
Novel Coronavirus ◽  
Further Development

<p>Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), previously known as 2019 novel coronavirus (2019-nCoV), has spread rapidly across the globe, creating an unparalleled global health burden and spurring a deepening economic crisis. As of July 7th, 2020, almost seven months into the outbreak, there are no approved vaccines and few treatments available. Developing drugs that target multiple points in the viral life cycle could serve as a strategy to tackle the current as well as future coronavirus pandemics. Here we leverage the power of our recently developed <i>in silico</i> screening platform, VirtualFlow, to identify inhibitors that target SARS-CoV-2. VirtualFlow is able to efficiently harness the power of computing clusters and cloud-based computing platforms to carry out ultra-large scale virtual screens. In this unprecedented structure-based multi-target virtual screening campaign, we have used VirtualFlow to screen an average of approximately 1 billion molecules against each of 40 different target sites on 17 different potential viral and host targets in the cloud. In addition to targeting the active sites of viral enzymes, we also target critical auxiliary sites such as functionally important protein-protein interaction interfaces. This multi-target approach not only increases the likelihood of finding a potent inhibitor, but could also help identify a collection of anti-coronavirus drugs that would retain efficacy in the face of viral mutation. Drugs belonging to different regimen classes could be combined to develop possible combination therapies, and top hits that bind at highly conserved sites would be potential candidates for further development as coronavirus drugs. Here, we present the top 200 <i>in silico</i> hits for each target site. While in-house experimental validation of some of these compounds is currently underway, we want to make this array of potential inhibitor candidates available to researchers worldwide in consideration of the pressing need for fast-tracked drug development.</p>

scholarly journals Facile Synthesis of MoP-RuP2 with Abundant Interfaces to Boost Hydrogen Evolution Reactions in Alkaline Media

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2347
Author(s):  
Zhi Chen ◽  
Ying Zhao ◽  
Yuxiao Gao ◽  
Zexing Wu ◽  
Lei Wang
Keyword(s):  
Hydrogen Evolution ◽  
Active Sites ◽  
Large Scale ◽  
Hydrogen Gas ◽  
Alkaline Media ◽  
Hydrogen Energy ◽  
Practical Applications ◽  
Melamine Phosphate ◽  
Hydrogen Evolution Reactions ◽  
A Current

Exploiting efficient electrocatalysts for hydrogen evolution reactions (HERs) is important for boosting the large-scale applications of hydrogen energy. Herein, MoP-RuP2 encapsulated in N,P-codoped carbon (MoP-RuP2@NPC) with abundant interfaces were prepared via a facile avenue with the low-toxic melamine phosphate as the phosphorous resource. Moreover, the obtained electrocatalyst possessed a porous nanostructure, had abundant exposed active sites and improved the mass transport during the electrocatalytic process. Due to the above merits, the prepared MoP-RuP2@NPC delivered a greater electrocatalytic performance for HERs (50 mV@10 mA cm−2) relative to RuP2@NPC (120 mV) and MoP@NPC (195 mV) in 1 M KOH. Moreover, an ultralow potential of 1.6 V was required to deliver a current density of 10 mA cm−2 in the two-electrode configuration for overall water splitting. For practical applications, intermittent solar energy, wind energy and thermal energy were utilized to drive the electrolyzer to generate hydrogen gas. This work provides a novel and facile strategy for designing highly efficient and stable nanomaterials toward hydrogen production.

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