scholarly journals Time-resolved photodissociation of singly protonated peptides with an arginine at the N-terminus: A statistical interpretation

2008 ◽  
Vol 19 (5) ◽  
pp. 645-655 ◽  
Author(s):  
So Hee Yoon ◽  
Yeon Ji Chung ◽  
Myung Soo Kim
Keyword(s):  
Statistical Interpretation ◽  
Time Resolved ◽  
Protonated Peptides ◽  
N Terminus

scholarly journals Use of time-resolved FRET to validate crystal structure of complement regulatory complex between C3b and factor H (N terminus)

2011 ◽  
Vol 20 (12) ◽  
pp. 2102-2112 ◽  
Author(s):  
Isabell C. Pechtl ◽  
Robert K. Neely ◽  
David T.F. Dryden ◽  
Anita C. Jones ◽  
Paul N. Barlow
Keyword(s):  
Crystal Structure ◽  
Factor H ◽  
Time Resolved ◽  
Use Of Time ◽  
N Terminus ◽  
Regulatory Complex

scholarly journals Structural plasticity of CENP-A regulated by H4 influences cellular levels and kinetochore assembly

2018 ◽  
Author(s):  
Nikita Malik ◽  
Sarath Chandra Dantu ◽  
Mamta Kombrabail ◽  
Santanu Kumar Ghosh ◽  
Guruswamy Krishnamoorthy ◽  
...  
Keyword(s):  
Regulatory Mechanism ◽  
Time Resolved Fluorescence ◽  
Core Component ◽  
Domain Interaction ◽  
Time Resolved ◽  
Closed Conformation ◽  
Kinetochore Assembly ◽  
N Terminus ◽  
Conformational Regulation ◽  
First Time

AbstractThe Histone variant CENP-ACse4 is a core component of the specialized nucleosome at the centromere in budding yeast. The level of Cse4 in cells is tightly regulated, primarily by ubiquitin-mediated proteolysis. However, the structural transitions in Cse4 that regulate centromere localization and interaction with regulatory components are poorly understood. Using time resolved fluorescence, NMR and molecular dynamics we show for the first time that soluble Cse4 can exist in a ‘closed’ conformation, inaccessible to various regulatory components. We further determined that binding of its obligate partner H4, alters the inter-domain interaction within Cse4, ensuring an ‘open’ state that will lend itself to proteolysis. This dynamic model allows kinetochore formation only in presence of H4, as the N-terminus, which is required for interaction with centromeric components will be unavailable in absence of H4. The specific requirement of H4 binding for the conformational regulation of Cse4 suggests a unique structure-based regulatory mechanism for Cse4 localization and prevention of premature kinetochore assembly.

Microtubule nucleation sequence studied by time-resolved x-ray scattering and electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 766-767
Author(s):  
Eva-Maria Mandelkow ◽  
Eckhard Mandelkow ◽  
Joan Bordas
Keyword(s):  
Electron Microscopy ◽  
Dynamic Equilibrium ◽  
Time Resolved ◽  
X Ray ◽  
Additional Information ◽  
X Ray Scattering ◽  
Low Concentrations ◽  
Microtubule Growth ◽  
Ray Patterns ◽  
Ray Scattering

When a solution of microtubule protein is changed from non-polymerising to polymerising conditions (e.g. by temperature jump or mixing with GTP) there is a series of structural transitions preceding microtubule growth. These have been detected by time-resolved X-ray scattering using synchrotron radiation, and they may be classified into pre-nucleation and nucleation events. X-ray patterns are good indicators for the average behavior of the particles in solution, but they are difficult to interpret unless additional information on their structure is available. We therefore studied the assembly process by electron microscopy under conditions approaching those of the X-ray experiment. There are two difficulties in the EM approach: One is that the particles important for assembly are usually small and not very regular and therefore tend to be overlooked. Secondly EM specimens require low concentrations which favor disassembly of the particles one wants to observe since there is a dynamic equilibrium between polymers and subunits.

Electron Channeling Patterns

1977 ◽  
Vol 35 ◽  
pp. 12-13
Author(s):  
David C. Joy
Keyword(s):  
Electron Diffraction ◽  
Incidence Angle ◽  
Photographic Plate ◽  
Diffraction Effect ◽  
Angle Of Incidence ◽  
Bulk Single Crystal ◽  
Time Resolved ◽  
Electron Channeling ◽  
Spatially Resolved ◽  
Large Bulk

Electron channeling patterns (ECP) were first found by Coates (1967) while observing a large bulk, single crystal of silicon in a scanning electron microscope. The geometric pattern visible was shown to be produced as a result of the changes in the angle of incidence, between the beam and the specimen surface normal, which occur when the sample is examined at low magnification (Booker, Shaw, Whelan and Hirsch 1967).A conventional electron diffraction pattern consists of an angularly resolved intensity distribution in space which may be directly viewed on a fluorescent screen or recorded on a photographic plate. An ECP, on the other hand, is produced as the result of changes in the signal collected by a suitable electron detector as the incidence angle is varied. If an integrating detector is used, or if the beam traverses the surface at a fixed angle, then no channeling contrast will be observed. The ECP is thus a time resolved electron diffraction effect. It can therefore be related to spatially resolved diffraction phenomena by an application of the concepts of reciprocity (Cowley 1969).

Time-resolved high-resolution electron microscopy of structural stability in mgo clusters

1996 ◽  
Vol 54 ◽  
pp. 672-673
Author(s):  
T. Kizuka ◽  
N. Tanaka
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Magnesium Oxide ◽  
Structural Stability ◽  
High Resolution Electron Microscopy ◽  
Video Tape ◽  
Solid State Physics ◽  
Time Resolved ◽  
Resolution Electron ◽  
Structural And Functional Properties

Structure and stability of atomic clusters have been studied by time-resolved high-resolution electron microscopy (TRHREM). Typical examples are observations of structural fluctuation in gold (Au) clusters supported on silicon oxide films, graphtized carbon films and magnesium oxide (MgO) films. All the observations have been performed on the clusters consisted of single metal element. Structural stability of ceramics clusters, such as metal-oxide, metal-nitride and metal-carbide clusters, has not been observed by TRHREM although the clusters show anomalous structural and functional properties concerning to solid state physics and materials science.In the present study, the behavior of ceramic, magnesium oxide (MgO) clusters is for the first time observed by TRHREM at 1/60 s time resolution and at atomic resolution down to 0.2 nm.MgO and gold were subsequently deposited on sodium chloride (001) substrates. The specimens, single crystalline MgO films on which Au particles were dispersed were separated in distilled water and observed by using a 200-kV high-resolution electron microscope (JEOL, JEM2010) equipped with a high sensitive TV camera and a video tape recorder system.

Cryo-TEM of amphiphilic polymer and amphiphile/polymer solutions

1993 ◽  
Vol 51 ◽  
pp. 876-877
Author(s):  
Yeshayahu Talmon
Keyword(s):  
Microstructural Characterization ◽  
Building Blocks ◽  
Quantitative Information ◽  
Physical Models ◽  
Specimen Preparation ◽  
Time Resolved ◽  
Temperature Changes ◽  
Temperature And Humidity ◽  
Microstructured Fluids ◽  
Air Streams

To achieve complete microstructural characterization of self-aggregating systems, one needs direct images in addition to quantitative information from non-imaging, e.g., scattering or Theological measurements, techniques. Cryo-TEM enables us to image fluid microstructures at better than one nanometer resolution, with minimal specimen preparation artifacts. Direct images are used to determine the “building blocks” of the fluid microstructure; these are used to build reliable physical models with which quantitative information from techniques such as small-angle x-ray or neutron scattering can be analyzed.To prepare vitrified specimens of microstructured fluids, we have developed the Controlled Environment Vitrification System (CEVS), that enables us to prepare samples under controlled temperature and humidity conditions, thus minimizing microstructural rearrangement due to volatile evaporation or temperature changes. The CEVS may be used to trigger on-the-grid processes to induce formation of new phases, or to study intermediate, transient structures during change of phase (“time-resolved cryo-TEM”). Recently we have developed a new CEVS, where temperature and humidity are controlled by continuous flow of a mixture of humidified and dry air streams.

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