Send to:

Choose Destination
See comment in PubMed Commons below
J Mol Biol. 2002 May 31;319(2):433-47.

The mechanical hierarchies of fibronectin observed with single-molecule AFM.

Author information

  • 1Department of Physiology and Biophysics, Mayo Foundation, Rochester, MN 55905, USA.


Mechanically induced conformational changes in proteins such as fibronectin are thought to regulate the assembly of the extracellular matrix and underlie its elasticity and extensibility. Fibronectin contains a region of tandem repeats of up to 15 type III domains that play critical roles in cell binding and self-assembly. Here, we use single-molecule force spectroscopy to examine the mechanical properties of fibronectin (FN) and its individual FNIII domains. We found that fibronectin is highly extensible due to the unfolding of its FNIII domains. We found that the native FNIII region displays strong mechanical unfolding hierarchies requiring 80 pN of force to unfold the weakest domain and 200 pN for the most stable domain. In an effort to determine the identity of the weakest/strongest domain, we engineered polyproteins composed of an individual domain and measured their mechanical stability by single-protein atomic force microscopy (AFM) techniques. In contrast to chemical and thermal measurements of stability, we found that the tenth FNIII domain is mechanically the weakest and that the first and second FNIII domains are the strongest. Moreover, we found that the first FNIII domain can acquire multiple, partially folded conformations, and that their incidence is modulated strongly by its neighbor FNIII domain. The mechanical hierarchies of fibronectin demonstrated here may be important for the activation of fibrillogenesis and matrix assembly.

Copyright 2002 Elsevier Science Ltd.

[PubMed - indexed for MEDLINE]

LinkOut - more resources

Full Text Sources

Other Literature Sources

PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Elsevier Science
    Loading ...
    Write to the Help Desk