scholarly journals Rational design of functional materials guided by single particle chemiluminescence imaging

2019 ◽  
Vol 10 (21) ◽  
pp. 5444-5451 ◽  
Author(s):  
Weijun Kong ◽  
Qi Li ◽  
Wei Wang ◽  
Xiaoning Zhao ◽  
Shenglong Jiang ◽  
...  
Keyword(s):  
Structural Characterization ◽  
Single Particle ◽  
Rational Design ◽  
Functional Materials ◽  
Single Particles ◽  
Improved Performance

Correlated chemiluminescence imaging and structural characterization of single particles helped the rational design of functional materials with significantly improved performance.

Uncovering the structures of modular polyketide synthases

2015 ◽  
Vol 32 (3) ◽  
pp. 436-453 ◽  
Author(s):  
Kira J. Weissman
Keyword(s):  
Electron Microscopy ◽  
Structural Biology ◽  
Structural Characterization ◽  
Small Angle ◽  
Single Particle ◽  
Polyketide Synthases ◽  
X Ray ◽  
X Ray Scattering ◽  
Cryo Electron Microscopy

This review covers a breakthrough in the structural biology of the gigantic modular polyketide synthases (PKS): the structural characterization of intact modules by single-particle cryo-electron microscopy and small-angle X-ray scattering.

scholarly journals In Crystallo Snapshots of Rh2-Catalyzed C–H Amination

2020 ◽  
Author(s):  
Anuvab Das ◽  
Chen-Hao Wang ◽  
Gerard Van Trieste ◽  
Cheng-Jun Sun ◽  
Yu-Sheng Chen ◽  
...  
Keyword(s):  
Structural Characterization ◽  
Rational Design ◽  
Transition Metal Catalysts ◽  
Catalyst Structure ◽  
Model Complexes ◽  
X Ray Crystallography ◽  
Transient Nature ◽  
Transient Intermediates ◽  
The Impact

<div> <div> <div> <p>Correlation of catalyst structure with activity is foundational to the rational design of transition metal catalysts. While X-ray crystallography routinely provides structural characterization of kinetically stable pre-catalysts and intermediates, experimental elucidation of the structures of reactive intermediates, which are the species intimately engaged in bond-breaking and -making in catalysis, is generally not possible due to the transient nature of these species. Here, we demonstrate in crystallo synthesis of Rh2 nitrenes that participate in catalytic C–H amination, and characterization of these transient intermediates as triplet adducts of Rh2. Further, we observe the impact of coordinating substrate, which is present in excess during catalysis, on the structure of transient Rh2 nitrenes involved in C–H amination. By providing structural characterization of authentic C–H functionalization intermediates, and not kinetically stabilized model complexes, these experiments provide the opportunity to define critical structure-activity relationships. </p> </div> </div> </div>

Structural Characterization of Ordered Phases in Hydrocarbon Dendrimers

1994 ◽  
Vol 351 ◽  
Author(s):  
Christopher J. Buchko ◽  
Atisa Sioshansi ◽  
Zhifu Xu ◽  
Jeffrey S. Moore ◽  
David C. Martin
Keyword(s):  
Structural Characterization ◽  
Rational Design ◽  
Structural Information ◽  
Molecular Architecture ◽  
Thermal Transitions ◽  
Self Assembling ◽  
Transmission Electron ◽  
Ordered Phases ◽  
Construction Of Self

ABSTRACTStructural characterization of phenylacetylene dendrimers (PADs) makes it possible to explore the relationship between molecular architecture and condensed phase organization. The size and geometry of the PAD series is precisely controlled, with phenylacetylene units emanating from a central phenylene in the manner of a tridendron. The branched molecule rapidly increases in size with each synthetic generation. The “shape-persistent” nature of the phenylacetylene molecule makes it ideal for use in the construction of self-assembling supramolecular systems.Transmission electron microscopy (TEM) has been used to identify the crystal structure of lower generation PADs, and wide-angle X-ray studies confirm the decrease in crystallinity with size. Hot stage optical microscopy studies of thermal transitions reveal melting points for lower generation PADs, and an apparent glass transition for the amorphous higher generations. This type of structural information is essential to the rational design of self-assembling materials.

scholarly journals Molecular details of sugar biosynthesis in mycobacteria

2014 ◽  
Vol 70 (a1) ◽  
pp. C1659-C1659
Author(s):  
Joana Fraga ◽  
Alexandra Silva ◽  
Ana Maranha ◽  
Vitor Mendes ◽  
Susana Alarico ◽  
...  
Keyword(s):  
Cell Wall ◽  
Structural Characterization ◽  
Rational Design ◽  
Three Dimensional ◽  
Molecular Targets ◽  
Molecular Models ◽  
Multiple Drugs ◽  
Drug Leads ◽  
Wall Components

Despite the research efforts of decades, Mycobacterium tuberculosis is still in the origin of 1.3 million deaths annually (WHO, Tuberculosis, 2013) and is estimated to infect 2 billion people worldwide. The currently available antimicrobial therapies are aimed at only a few molecular targets and the growing number of strains resistant to multiple drugs drives an urgent need for the identification of novel pathways and new points for therapeutic intervention. Although the sequence of the M. tuberculosis genome has been known for more than a decade, there is still no function assigned to many of its genes. Among M. tuberculosis ORFs with known function, more than 1% encode enzymes involved in glycosidic bond synthesis. Since the increased resilience of M. tuberculosis is, to a great extent, due to its complex, polysaccharide/lipid-rich and thus unusually impermeable cell wall, we became interested on the functional and structural characterization of mycobacterial enzymes involved in biosynthetic pathways for cell wall components. Over the last few years, we have carried out the functional and structural characterization of novel enzymes in the sugar biosynthesis metabolic routes from thermostable and mesostable mycobacteria [1-3]. Recently, we characterized functionally two enzymes from M. vanbalenii and M. hassiacum whose orthologs in M. tuberculosis are essential for growth, and determined their three-dimensional structures to high resolution (1.2-1.5 Å), allowing the thorough elucidation of their intricate nucleotide and sugar specificities. These experimental molecular models will be presented as examples of frameworks for the rational design of novel anti-mycobacterial drug leads. (Funded by national funds through FCT and by EU-FEDER funding through COMPETE (grants FCOMP-01-0124-FEDER-014321, FCOMP-01-0124-FEDER-014187, FCOMP-01-0124-FEDER-028359) and through ON.2-O Novo Norte, under QREN (grant NORTE-07-0124-000002 - Host-Pathogen Interactions).

scholarly journals In Crystallo Snapshots of Rh2-Catalyzed C–H Amination

2020 ◽  
Author(s):  
Anuvab Das ◽  
Chen-Hao Wang ◽  
Gerard Van Trieste ◽  
Cheng-Jun Sun ◽  
Yu-Sheng Chen ◽  
...  
Keyword(s):  
Structural Characterization ◽  
Rational Design ◽  
Transition Metal Catalysts ◽  
Catalyst Structure ◽  
Model Complexes ◽  
X Ray Crystallography ◽  
Transient Nature ◽  
Transient Intermediates ◽  
The Impact

<div> <div> <div> <p>Correlation of catalyst structure with activity is foundational to the rational design of transition metal catalysts. While X-ray crystallography routinely provides structural characterization of kinetically stable pre-catalysts and intermediates, experimental elucidation of the structures of reactive intermediates, which are the species intimately engaged in bond-breaking and -making in catalysis, is generally not possible due to the transient nature of these species. Here, we demonstrate in crystallo synthesis of Rh2 nitrenes that participate in catalytic C–H amination, and characterization of these transient intermediates as triplet adducts of Rh2. Further, we observe the impact of coordinating substrate, which is present in excess during catalysis, on the structure of transient Rh2 nitrenes involved in C–H amination. By providing structural characterization of authentic C–H functionalization intermediates, and not kinetically stabilized model complexes, these experiments provide the opportunity to define critical structure-activity relationships. </p> </div> </div> </div>

scholarly journals Structural characterization of NDH-1 complexes of Thermosynechococcus elongatus by single particle electron microscopy

2006 ◽  
Vol 1757 (11) ◽  
pp. 1469-1475 ◽  
Author(s):  
Ana A. Arteni ◽  
Pengpeng Zhang ◽  
Natalia Battchikova ◽  
Teruo Ogawa ◽  
Eva-Mari Aro ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Structural Characterization ◽  
Single Particle ◽  
Single Particle Electron Microscopy

scholarly journals Structural Characterization of the Helicobacter Pylori VacA Toxin by Single Particle Em and X-Ray Crystallography

2013 ◽  
Vol 104 (2) ◽  
pp. 21a
Author(s):  
Melissa G. Chambers ◽  
Tasia Pyburn ◽  
Christian González-Rivera ◽  
Scott E. Collier ◽  
Yoshimasa Takizawa ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Structural Characterization ◽  
Single Particle ◽  
X Ray ◽  
X Ray Crystallography

New ultrastructural findings about Borrelia burgdorferi by cryofixation, negative staining, thin sectioning and scanning techniques

1990 ◽  
Vol 48 (3) ◽  
pp. 582-583
Author(s):  
S. F. Hayes ◽  
M. D. Corwin ◽  
T. G. Schwan ◽  
D. W. Dorward ◽  
W. Burgdorfer
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Structural Characterization ◽  
Negative Staining ◽  
Low Speed ◽  
Thin Sectioning ◽  
Ultrastructural Findings

Characterization of Borrelia burgdorferi strains by means of negative staining EM has become an integral part of many studies related to the biology of the Lyme disease organism. However, relying solely upon negative staining to compare new isolates with prototype B31 or other borreliae is often unsatisfactory. To obtain more satisfactory results, we have relied upon a correlative approach encompassing a variety EM techniques, i.e., scanning for topographical features and cryotomy, negative staining and thin sectioning to provide a more complete structural characterization of B. burgdorferi.For characterization, isolates of B. burgdorferi were cultured in BSK II media from which they were removed by low speed centrifugation. The sedimented borrelia were carefully resuspended in stabilizing buffer so as to preserve their features for scanning and negative staining. Alternatively, others were prepared for conventional thin sectioning and for cryotomy using modified procedures. For thin sectioning, the fixative described by Ito, et al.

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