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Published October 1996 | public
Journal Article

Observation of a Silk-Like Crystal Structure in a Genetically Engineered Periodic Polypeptide

Abstract

A genetically engineered periodic polypeptide consisting of 36 repeats of the octapeptide sequence -(AlaGly)_3GluGly- has been crystallized from solution in aqueous lithium bromide. Analysis by solid-state nuclear magnetic resonance spectroscopy, vibrational spectroscopy, and wide-angle x-ray diffraction reveals a crystal structure analogous to that obtained when silk solutions are allowed to dry under quiescent conditions, i.e., the silk I structure. Previous analyses of the same polymer have demonstrated an antiparallel β-sheet architecture (silk II structure) in samples crystallized from formic acid. These results illustrate the potential for controlling the solid-state structures and properties of genetically engineered materials through selection of appropriate processing and crystallization conditions.

Additional Information

© 1996 Marcel Dekker. We thank S. L. Hsu for guidance in vibrational spectroscopy, and L. K. Thompson for help in obtaining solid-state NMR spectra. This work was supported by grants from the Polymers and Genetics Programs of the National Science Foundation, and by the NSF Materials Research Science and Engineering Center at the University of Massachusetts.

Additional details

Created:
August 19, 2023
Modified:
October 20, 2023