Understanding the elasticity of fibronectin fibrils: unfolding strengths of FN-III and GFP domains measured by single molecule force spectroscopy.

Published

Journal Article

While it is well established that fibronectin (FN) matrix fibrils are elastic, the mechanism of fibril elasticity during extension is still debated. To investigate the molecular origin of FN fibril elasticity, we used single molecule force spectroscopy (SMFS) to determine the unfolding behavior of a recombinant FN-III protein construct that contained eight FN-III domains ((1-8)FN-III) and two green fluorescent protein (GFP) domains. FN-III domains were distinguished from GFP domains by their shorter unfolding lengths. The unfolding strengths of both domains were determined for a wide range of pulling rates (50 to 1,745 nm/s). We found that the mechanical stabilities of FN-III and GFP domains were very similar to each other over the entire range of pulling speeds. FN fibrils containing GFP remain brightly fluorescent, even when stretched, meaning that GFP domains remain largely folded. Since GFP and FN-III have equal unfolding strengths, this suggests that FN-III domains are not extensively unraveled in stretched FN fibrils. Our results thus favor an alternative model, which invokes a conformational change from a compact to an extended conformation, as the basis for FN fibril elasticity.

Full Text

Duke Authors

Cited Authors

  • Abu-Lail, NI; Ohashi, T; Clark, RL; Erickson, HP; Zauscher, S

Published Date

  • April 2006

Published In

Volume / Issue

  • 25 / 3

Start / End Page

  • 175 - 184

PubMed ID

  • 16343877

Pubmed Central ID

  • 16343877

International Standard Serial Number (ISSN)

  • 0945-053X

Digital Object Identifier (DOI)

  • 10.1016/j.matbio.2005.10.007

Language

  • eng

Conference Location

  • Netherlands