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Published September 2, 1994 | metadata_only
Journal Article

Chemical sequence control of β-sheet assembly in macromolecular crystals of periodic polypeptides


A family of uniform periodic. polypeptides has been prepared by bacterial expression of the corresponding artificial genes, with the objective of exploring the potential for control of supramolecular organization in genetically engineered protein-based polymeric materials. The repeating units of the polypeptides consist of oligomeric alanylglycine sequences interspersed with glutamic acid residues inserted at intervals of 8 to 14 amino acids. Crystallization of such materials from formic acid produces β-sheet structures in the solid state, as shown by vibrational spectroscopy, nuclear magnetic resonance spectroscopy, and wide-angle x-ray diffraction. The diffraction results, together with observations from electron microscopy, are consistent with the formation of needle-shaped lamellar crystals whose thickness is controlled by the periodicity of the primary sequence. These results can be used to control solid-state structure in macromolecular materials.

Additional Information

© 1994 American Association for the Advancement of Science. 4 April 1994; accepted 7 July 1994. We thank J. Cappello for the gift of p937.51 and for helpful advice. S. L. Hsu for guidance in vibrational spectroscopy and L. K. Thompson for help in obtaining solid-state NMR spectra. Y. Deguchi developed methods for the preparation of polymers 1b through 1d. We are grateful to A. D. Parkhe for preparing Fig. 2 and to S. Cooper for Fig. 8. Supported by grants from the Polymers and Genetics Programs of the National Science Foundation (NSF) and by the NSF Materials Research Laboratory at the University of Massachusetts.

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August 20, 2023
August 20, 2023