HELICAL PARAMETERS OF REGULAR π-HELICES IN PROTEINS (Part 2)

2016 ◽  
Vol 4 ◽  
pp. 17-25
Author(s):  
Batkhishig D. ◽  
◽  
Mijiddorj B. ◽  
Enkhbayar P. ◽  
◽  
...  
Keyword(s):  
Helical Parameters

The three-dimensional structure of frozen-hydrated left- and right-handed forms of bacterial flagellar filaments from an identical serotype

1986 ◽  
Vol 44 ◽  
pp. 298-299
Author(s):  
S. Trachtenberg ◽  
D. J. DeRosier
Keyword(s):  
Ionic Strength ◽  
Basal Body ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Protein Species ◽  
Liquid Environment ◽  
Bacterial Flagellum ◽  
Left And Right ◽  
Rotary Motor ◽  
Helical Parameters

The bacterial cell is propelled through the liquid environment by means of one or more rotating flagella. The bacterial flagellum is composed of a basal body (rotary motor), hook (universal coupler), and filament (propellor). The filament is a rigid helical assembly of only one protein species — flagellin. The filament can adopt different morphologies and change, reversibly, its helical parameters (pitch and hand) as a function of mechanical stress and chemical changes (pH, ionic strength) in the environment.

scholarly journals 1P184 Classification of the flagellar polymorphic family by helical parameters

2005 ◽  
Vol 45 (supplement) ◽  
pp. S77
Author(s):  
M. Fujii ◽  
S. Shibata ◽  
S. Aizawa
Keyword(s):  
Helical Parameters

scholarly journals 1P289 Helical parameters of alpha-helices in proteins

2005 ◽  
Vol 45 (supplement) ◽  
pp. S104
Author(s):  
Purejav Eahkbayar ◽  
M. Osaki ◽  
N. Matsushima
Keyword(s):  
Alpha Helices ◽  
Helical Parameters

scholarly journals Actin in triton-treated cortical preparations of unfertilized and fertilized sea urchin eggs.

1979 ◽  
Vol 82 (1) ◽  
pp. 212-226 ◽  
Author(s):  
A Spudich ◽  
J A Spudich
Keyword(s):  
Electron Microscopy ◽  
Sea Urchin ◽  
Actin Filaments ◽  
Cell Types ◽  
Optical Diffraction ◽  
Muscle Actin ◽  
Sea Urchin Eggs ◽  
Inner Surface ◽  
Low Ionic Strength ◽  
Helical Parameters

Triton-treated cortical fragments of unfertilized and fertilized sea urchin eggs prepared in the presence of greater than or equal to 5 mM EGTA contain 15-30% of the total egg actin. However, actin filaments are not readily apparent by electron microscopy on the cortical fragments of unfertilized eggs but are numerous on those of fertilized eggs. The majority of the actin associated with cortical fragments of unfertilized eggs is solubilized by dialysis against a low ionic strength buffer at pH 7.5. This soluble actin preparation (less than 50% pure actin) does not form proper filaments in 0.1 M KCl and 3 mM MgCl2, whereas actin purified from this preparation does, as judged by electron microscopy. Optical diffraction analysis reveals that these purified actin filaments have helical parameters very similar to those of muscle actin. Furthermore, the properties of the purified actin with regard to activation of myosin ATPase are similar to those of actin from other cell types. The possibility that actin is maintained in a nonfilamentous form on the inner surface of the unfertilized egg plasma membrane and is induced to assemble upon fertilization is discussed.

A program for the computation of helical parameters from internal coordinates

1980 ◽  
Vol 11 (1) ◽  
pp. 3-8 ◽  
Author(s):  
Silvano Colombano ◽  
Robert Rein ◽  
Robert D. MacElroy
Keyword(s):  
Internal Coordinates ◽  
Helical Parameters

Computation of 3D structure and distribution of helical parameters for D-period segments of human fibrillar collagen III

BIOPHYSICS ◽  
2007 ◽  
Vol 52 (6) ◽  
pp. 567-574 ◽  
Author(s):  
S. A. Lukshin ◽  
I. V. Filatov ◽  
J. V. Milchevsky ◽  
A. D. Sushko ◽  
Yu. V. Kravatsky ◽  
...  
Keyword(s):  
3D Structure ◽  
Fibrillar Collagen ◽  
Collagen Iii ◽  
Helical Parameters

Cryo-electron microscopy of chromosome fibers is consistent with the crossed-linker model for chromatin structure

1987 ◽  
Vol 45 ◽  
pp. 648-649
Author(s):  
B. Athey ◽  
J. Langmore ◽  
S. Williams ◽  
M. Smith ◽  
C.F. Chang ◽  
...  
Keyword(s):  
Chromatin Structure ◽  
Double Helix ◽  
Histone Octamer ◽  
Left Handed ◽  
Variable Diameter ◽  
Cryo Electron Microscopy ◽  
Constant Diameter ◽  
Constant Pitch ◽  
Conserved Core ◽  
Helical Parameters

Although there is general agreement that inactive chromosome fibers consist of helically packed nucleosomes, the pattern of packing is still disputed. The nucleosome itself is composed of a highly conserved “core” comprised of 146bp of DNA and a histone octamer, and a variable “linker” comprised of 20-100bp of DNA bound to histone H1. The models of chromatin structure can be distinguished by their dependence upon linker length. The solenoid model for chromatin structure is a single helix with constant pitch (11 nm) and constant diameter (25-30nm). The twisted-ribbon model is a double helix with variable pitch (26-40nm) and constant diameter (30nm). The crossed-linker model is a double helix with conserved pitch (26-28nm) and variable diameter (26-40nm). Measurements of the diameter and apparent helical parameters of negatively-stained chromatin from Thyone sperm (87bp linker) and Necturus erythrocytes (48bp linker) are in agreement with a left-handed crossed-linker model, and in disagreement with the solenoid and twisted-ribbon models.

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