PolySacDb

A Database of Polysachharide 3D structures

 
By A. Sarkar & S. Pérez
 
 
 

Polysaccharides For Experts

Amylose A (fiber, powder and electron diffraction)

 

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Diffraction Diagram

 

Fig.1 Examples of electron diffraction diagrams recorded under frozen wet conditions from crystals rotated about their long axis. The indexations and the corresponding zone axes of these diagrams are also presented.

(a)The goniometer setting was (a) 36°, (b) -10° (c) +20°.

 

Fig.2 Examples of electron diffraction diagrams recorded under frozen wet conditions from crystals rotated about an axis perpendicular to their long direction. In (a) reflection 2 is twice as intense as that in 1. In (b) reflection 3 is slightly less intense than 1, 2 and 3 which index as --1-2-1 and --1 2-1 in an orthorhombic system, should have equivalent intensities. This is not the case and hence the monoclinic indexation is favoured.

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  Amylose A (fiber, powder and electron diffraction)

Linkage :       alpha 1-4     

 

Space Group :       monoclinic B2

 

Unit Cell Dimensions (a, b, c in Å and α, β, γ in °)

(No values are displayed if no information is available or the value is zero)

a (Å) =   21.24

b (Å) =   11.72

c (Å) =   10.69

 

γ (°) =   123.00

 

Helix Type :      

two left-handed, parallel-stranded double helices packed in a parallel fashion

 

Method(s) Used For Structure Determination :      

electron diffraction, X-ray powder patterns and X-ray fibre diffraction data

 

Link to the Abstract :      
 
http://www.ncbi.nlm.nih.gov/pubmed/3418703

 

Reference :      

The Double-helical Nature of the Crystalline Part of A-Starch
Anne Imberty, Henri Chanzy, Serge Pérez, Alain Buléon and Vinh Tran, 1988, J. Mol. Biol, 201, 365-378

 

 

Download Structure

Unit          AmyA_double          amylose-a_expanded

 

 

 

 

 
   
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