ISSN:
0006-3525
Keywords:
monolayer
;
silk
;
fibroin
;
Bombyx mori
;
protein surfactancy
;
air-water interface
;
Langmuir - Blodgett film
;
Langmuir monolayer
;
silkworm
;
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
A new crystalline polymorph of Bombyx mori silk, which forms at the air-water interface, has been characterized. A previous study found this structure to be trigonal, and to be distinctly different than the two previously observed silk crystal structures, silk I and silk II. This new structure was named silk III. Identification of this new silk polymorph was based on evidence from transmission electron microscopy and electron diffraction, coupled with molecular modeling. In the current paper, additional data enables us to refine our model of the silk III structure. Some single crystal electron diffraction patterns indicate a deviation in symmetry away from a perfect trigonal unit cell to monoclinic unit cell. The detailed shape of the powder diffraction peaks also supports a monoclinic cell. The monoclinic crystal structure has an nonprimitive unit cell incorporating a slightly distorted hexagonal packing of silk molecular helices. The chains each assume a threefold helical conformation, resulting in a crystal structure similar to that observed for polyglycine II, but with some additional sheet-like packing features common to the threefold helical crystalline forms of many glycine-rich polypeptides. © 1997 John Wiley & Sons, Inc. Biopoly 42: 705-717, 1997
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
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