Entropic elasticity controls nanomechanics of single tropocollagen molecules.

ABSTRACT: We report molecular modeling of stretching single molecules of tropocollagen, the building block of collagen fibrils and fibers that provide mechanical support in connective tissues. For small deformation, we observe a dominance of entropic elasticity. At larger deformation, we find a transition to energetic elasticity, which is characterized by first stretching and breaking of hydrogen bonds, followed by deformation of covalent bonds in the protein backbone, eventually leading to molecular fracture. Our force-displacement curves at small forces show excellent quantitative agreement with optical tweezer experiments. Our model predicts a persistence length xi(p) approximately 16 nm, confirming experimental results suggesting that tropocollagen molecules are very flexible elastic entities. W

SUBMITTER: Buehler MJ 

PROVIDER: S-EPMC1914436 | biostudies-literature | 2007 Jul

REPOSITORIES: biostudies-literature