Translational Diffusion Constants of Short Peptides: Measurement by NMR and Their Use in Structural Studies of Peptides

2009 ◽  
Vol 113 (27) ◽  
pp. 9326-9329 ◽  
Author(s):  
Hongxia Pei ◽  
Markus W. Germann ◽  
Stuart A. Allison
Keyword(s):  
Translational Diffusion ◽  
Short Peptides ◽  
Structural Studies ◽  
Diffusion Constants

scholarly journals Interactions of Human Fibrinogen in Solution

1977 ◽  
Author(s):  
E. Serrallach ◽  
W. Känzig ◽  
V. Hofmann ◽  
P.W. Straub ◽  
M. Zulauf
Keyword(s):  
Diffusion Coefficient ◽  
Brownian Motion ◽  
Rotational Diffusion ◽  
Sedimentation Coefficient ◽  
Translational Diffusion ◽  
Initial Slope ◽  
Single Pair ◽  
Human Fibrinogen ◽  
Diffusion Constants ◽  
End To End

The intriguing diversity of published translational diffusion constants for the fibrinogen molecule can hardly be explained, unless interactions between the molecules are postulated. In the present study we have investigated the possible effect of molecular association and electrostatic intermolecular interactions on the Brownian motion. The translational diffusion coefficient DT, the rotational diffusion coefficient around the minor axis DR and the sedimentation coefficient have been measured. The methods used were dynamic light scattering and analytical ultracentrifugation. The samples were solutions of purified human fibrinogen. The correlation-function corresponding to DT deviates from a single exponential. The initial slope is found to depend on concentration, being DT = (1.7 ± 0.3) 10-7 cm2/s at 10mg/ml, pH 7.4 and 0.15 molar Tris-NaCl, and increases at fibrinogen concentrations below 2mg/ml. These results are compatible with a polydispers solution, in which single molecules are in equilibrium with pair and higher aggregates. The nature of the aggregates is end-to-end as indicated from the difference between the two rotational diffusion constants DR = 40000 ± 20% and DR = 10000 ±30% s-1. On the basis of the Hall-Slayter model and assumption of end-to-end association we calculated the ratio of the sedimentation coefficient of single, pair and triplet associates, being 1:1.14:1.20. Therefore, it is difficult to separate them in a sedimentation run. For ionic strength below 0.05 molar and low fibrinogen concentration (0.lmg/ml) a fast decay appears in the correlation, indicating that the Brownian motion is strongly influenced by electrostatic interactions.

ESR measurement of translational diffusion constants

1995 ◽  
Vol 33 (13) ◽  
pp. S107-S113 ◽  
Author(s):  
Susan A. Fawthrop ◽  
Duncan G. Gillies ◽  
Leslie H. Sutcliffe ◽  
Mark R. Symms
Keyword(s):  
Translational Diffusion ◽  
Diffusion Constants

Simple EPR method for measuring translational diffusion constants

1995 ◽  
Vol 91 (5) ◽  
pp. 887 ◽  
Author(s):  
Caroline A. Beadle ◽  
Duncan G. Gillies ◽  
Leslie H. Sutcliffe ◽  
Xiaoping Wu
Keyword(s):  
Translational Diffusion ◽  
Epr Method ◽  
Diffusion Constants

Ribosome Structural Organization

1974 ◽  
Vol 32 ◽  
pp. 332-333
Author(s):  
James A. Lake
Keyword(s):  
Ribosomal Proteins ◽  
Structural Organization ◽  
Three Dimensional ◽  
Small Subunit ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
Specific Antibodies ◽  
X Ray ◽  
E Coli ◽  
Complete Sequences

The understanding of ribosome structure has advanced considerably in the last several years. Biochemists have characterized the constituent proteins and rRNA's of ribosomes. Complete sequences have been determined for some ribosomal proteins and specific antibodies have been prepared against all E. coli small subunit proteins. In addition, a number of naturally occuring systems of three dimensional ribosome crystals which are suitable for structural studies have been observed in eukaryotes. Although the crystals are, in general, too small for X-ray diffraction, their size is ideal for electron microscopy.

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