Polysaccharides

The objective of this article is to illustrate and visualize the structures and concepts of common polysaccharides that are difficult to visualize and illustrate by viewing two dimensional structures in textbooks. Structures with a 3D perspective are used to illustrate features of a molecule which can not be easily visualized using 2D structures.

spinqualitylabelsall models Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Amylose Amylose is an example of a polysccharide which contains thousands of glucoses connected by α(1→4) glycosidic bonds. The initial view (Reset initial scene) shows an eleven unit segment of amylose with yellow halos marking some of the oxygens which form the 1→4 glycosidic bonds. Rotate amylose to view the glucopyranosyl units on edge to see that the bonds are α linkages. (Remember: With the glucose providing C-1 on the left, the glucose providing C-4 on the right and C-6 of the glucoses projecting to the back of the screen both bonds of the oxygen of the α linkage project down.) From this perspective you are looking down the axis of a helix that is formed as a result of the angle that is form between the glucopyranosyl residues when they are connected by the α(1→4) bonds. This characteristic of the α(1→4) bond was seen when studying maltose. Color ends of the polymer yellow and green. Amylose with 20 glucose units; Spacefill display Amylopectin Amylopectin is also a large glucose polymer that has α(1→4) glycosidic bonds connecting the glucose units. Rotate Amylopectin to view the glucopyranosyl units on edge to see that the bonds are α linkages. but its structure is more complex because it also contains α(1→ 6) glycosidic bonds. The structure shown here has only one such bond (yellow halo on carbon #6), in order to keep the structure relatively simple. The green ring is the reducing end of the molecule. The chain that proceeds from the branching point is colored blue. The yellow rings are the non-reducing ends of the two branches. They just happen to be close to each other in this model. The structure is more open (helix is not wound as tight) than the amylose because more space is needed for the chain that is formed at the branching point. The native amylopectin having many more branching points would be more open than this structure, in fact it would have very little curvature. Rotating & zooming amylopectin gives a focused view of the α(1→ 6) bond. TextToBeDisplayed

spinqualitylabelsall models Insert caption here Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D

one cellulose chain

Show second chain

Other Carbohydrate Pages

• maltose
• Disaccharides

Proteopedia Page Contributors and Editors (what is this?)

Karl Oberholser, Karsten Theis