scholarly journals High-Pressure NMR Reveals Volume and Compressibility Differences Between Two Stably Folded Protein Conformations

2020 ◽  
Author(s):  
Xingjian Xu ◽  
Donald Gagné ◽  
James M. Aramini ◽  
Kevin H. Gardner
Keyword(s):  
High Pressure ◽  
Intermediate State ◽  
Quantitative Data ◽  
Protein Conformations ◽  
Beta Strand ◽  
Biomolecular Nmr ◽  
Unique Information ◽  
Lower Volume ◽  
Biophysical Study ◽  
Conformational Switches

ABSTRACTProteins often interconvert between different conformations in ways critical to their function. While manipulating such equilibria for biophysical study is often challenging, the application of pressure is a potential route to achieve such control by favoring the population of lower volume states. Here, we use this feature to study the interconversion of ARNT PAS-B Y456T, which undergoes a dramatic beta-strand slip as it switches between two stably-folded conformations. Coupling high pressure and biomolecular NMR, we obtained the first quantitative data testing two key hypotheses of this process: the slipped conformation is both smaller and less compressible than the wildtype equivalent, and the interconversion proceeds through a chiefly-unfolded intermediate state. Our work exemplifies how these approaches, which can be generally applied to protein conformational switches, can provide unique information that is not easily accessible through other techniques.

scholarly journals An Analysis of the Effect of Plunger Barrel Performance of High Pressure Pumps and Fuel Against the Main Engine Injector Performance

2019 ◽  
Author(s):  
Agus Tjahjono ◽  
Vega Fonsula Andromeda ◽  
Boedojo Wiwoho ◽  
Saifudin Afandi
Keyword(s):  
Social Sciences ◽  
High Pressure ◽  
Quantitative Data ◽  
Likert Scale ◽  
High Pressure Pump ◽  
Pressure Pump ◽  
The Social ◽  
Main Engine

This study aimed to analyze the magnitude of the performance correlation value of a plunger barrel of high pressure pump (X1) and fuel (Y1) in the main engine injector performance (Y). This study applied SPSS (Statistical Package for the Social Sciences) analysis which produces quantitative data to describe the object under the study. The data were collected through a questionnaire by using a Likert scale approach. The results showed that the X1 coefficient on variable Y was moderate but the correlation value of X2 to Y was low. The correlation value of the influence of variables X1 and X2 together on the variable Y was also low. This variable can be used as an analysis in assessing the performance of the main engine injector in commercial vessels.

scholarly journals Volume and compressibility differences between protein conformations revealed by high-pressure NMR

2021 ◽  
Author(s):  
Xingjian Xu ◽  
Donald Gagné ◽  
James M. Aramini ◽  
Kevin H. Gardner
Keyword(s):  
High Pressure ◽  
Protein Conformations

Metallurgical Effects of Grain Boundary Ledges

1977 ◽  
Vol 35 ◽  
pp. 126-129
Author(s):  
L.E. Murr
Keyword(s):  
Grain Boundary ◽  
Quantitative Data ◽  
Mechanical Treatment ◽  
Unit Length ◽  
Physical And Mechanical Properties ◽  
Direct Observations ◽  
Transmission Electron ◽  
Properties Of Materials ◽  
Thermo Mechanical Treatment ◽  
Ledge Density

Ledges in grain boundaries can be identified by their characteristic contrast features (straight, black-white lines) distinct from those of lattice dislocations, for example1,2 [see Fig. 1(a) and (b)]. Simple contrast rules as pointed out by Murr and Venkatesh2, can be established so that ledges may be recognized with come confidence, and the number of ledges per unit length of grain boundary (referred to as the ledge density, m) measured by direct observations in the transmission electron microscope. Such measurements can then give rise to quantitative data which can be used to provide evidence for the influence of ledges on the physical and mechanical properties of materials.It has been shown that ledge density can be systematically altered in some metals by thermo-mechanical treatment3,4.

High-pressure freezing of cells in suspension for low-voltage scanning electron microscopy (LVSEM)

1991 ◽  
Vol 49 ◽  
pp. 64-65
Author(s):  
Marek Malecki ◽  
James Pawley ◽  
Hans Ris
Keyword(s):  
Electron Microscopy ◽  
High Pressure ◽  
Low Voltage ◽  
Culture Media ◽  
Cell Structure ◽  
Freeze Substitution ◽  
Ice Crystal ◽  
High Pressure Freezing ◽  
Cell Culture Media ◽  
Voltage Scanning

The ultrastructure of cells suspended in physiological fluids or cell culture media can only be studied if the living processes are stopped while the cells remain in suspension. Attachment of living cells to carrier surfaces to facilitate further processing for electron microscopy produces a rapid reorganization of cell structure eradicating most traces of the structures present when the cells were in suspension. The structure of cells in suspension can be immobilized by either chemical fixation or, much faster, by rapid freezing (cryo-immobilization). The fixation speed is particularly important in studies of cell surface reorganization over time. High pressure freezing provides conditions where specimens up to 500μm thick can be frozen in milliseconds without ice crystal damage. This volume is sufficient for cells to remain in suspension until frozen. However, special procedures are needed to assure that the unattached cells are not lost during subsequent processing for LVSEM or HVEM using freeze-substitution or freeze drying. We recently developed such a procedure.

Prolonged Fixation Studies For Spaceflight

1973 ◽  
Vol 31 ◽  
pp. 332-333
Author(s):  
Robert Corbett ◽  
Delbert E. Philpott ◽  
Sam Black
Keyword(s):  
High Pressure ◽  
Living Systems ◽  
Prolonged Storage ◽  
Time Intervals ◽  
Early Signs ◽  
Large Numbers

Observation of subtle or early signs of change in spaceflight induced alterations on living systems require precise methods of sampling. In-flight analysis would be preferable but constraints of time, equipment, personnel and cost dictate the necessity for prolonged storage before retrieval. Because of this, various tissues have been stored in fixatives and combinations of fixatives and observed at various time intervals. High pressure and the effect of buffer alone have also been tried.Of the various tissues embedded, muscle, cartilage and liver, liver has been the most extensively studied because it contains large numbers of organelles common to all tissues (Fig. 1).

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