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Physical and chemical microstructure of spider dragline: A study by analytical transmission electron microscopy
Author(s) -
Thiel Brad L.,
Kunkel Dennis D.,
Viney Christopher
Publication year - 1994
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360340812
Subject(s) - microstructure , transmission electron microscopy , chemistry , spider , electron , electron microscope , nanotechnology , crystallography , optics , materials science , physics , quantum mechanics , astronomy
We report the first direct observations of the physical and chemical microstructure of spider dragline, revealed by analytical transmission electron microscopy. Individual crystallites were imaged within the amorphous matrix. They are irregularly shaped, approximately 70–100 nm in diameter, and uniformly distributed throughout the matrix. Electron diffraction determined their space group to be P2 1 . The corresponding orthogonal cell has lattice parameters of a = 13.31 Å (β‐sheet repeat), b = 9.44 Å (interchain repeat within β‐sheets), and c = 20.88 Å (repeat along polypeptide chain). Electron energy loss spectroscopy indicated compositional variations within the matrix, and between the crystallites and matrix. Most notably, calcium was found exclusively in the crystallites. Attempts to produce synthetic analogues of dragline, which exhibits an unparalleled combination of strength, stiffness, and toughness, cannot depend solely on duplicating the constituent proteins. The complex hierarchical microstructure of the natural material must be taken into account. © 1994 John Wiley & Sons, Inc.