Polysaccharide elasticity governed by chair-boat transitions of the glucopyranose ring.

Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, U.S. Gov't, P.H.S.

Many common, biologically important polysaccharides contain pyranose rings made of five carbon atoms and one oxygen atom. They occur in a variety of cellular structures, where they are often subjected to considerable tensile stress. The polysaccharides are thought to respond to this stress by elastic deformation, but the underlying molecular rearrangements allowing such a response remain poorly understood. It is typically assumed, however, that the pyranose ring structure is inelastic and locked into a chair-like conformation. Here we describe single-molecule force measurements on individual polysaccharides that identify the pyranose rings as the structural unit controlling the molecule's elasticity. In particular, we find that the enthalpic component of the polymer elasticity of amylose, dextran and pullulan is eliminated once their pyranose rings are cleaved. We interpret these observations as indicating that the elasticity of the three polysaccharides results from a force-induced elongation of the ring structure and a final transition from a chair-like to a boat-like conformation. We expect that the force-induced deformation of pyranose rings reported here plays an important role in accommodating mechanical stresses and modulating ligand binding in biological systems.

Full Text

Duke Authors

Cited Authors

  • Marszalek, PE; Oberhauser, AF; Pang, YP; Fernandez, JM

Published Date

  • December 17, 1998

Published In

Volume / Issue

  • 396 / 6712

Start / End Page

  • 661 - 664

PubMed ID

  • 9872313

International Standard Serial Number (ISSN)

  • 0028-0836

Digital Object Identifier (DOI)

  • 10.1038/25322

Language

  • eng

Citation Source

  • PubMed