Molecular tandem repeat strategy for elucidating mechanical properties of high-strength proteins

Abdon Pena-Francesch

Assistant Professor

abdon@umich.edu

Arriving January 2021

Bio

Publications


Huihun Jung, Abdon Pena-Francesch, Alham Saadat, Aswathy Sebastian, Dong H Kim, Reginald F Hamilton, Istvan Albert, Benjamin D Allen, and Melik C Demirel (2016)

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 113(23):6478-6483.

Many globular and structural proteins have repetitions in their sequences or structures. However, a clear relationship between these repeats and their contribution to the mechanical properties remains elusive. We propose a new approach for the design and production of synthetic polypeptides that comprise one or more tandem copies of a single unit with distinct amorphous and ordered regions. Our designed sequences are based on a structural protein produced in squid suction cups that has a segmented copolymer structure with amorphous and crystalline domains. We produced segmented polypeptides with varying repeat number, while keeping the lengths and compositions of the amorphous and crystalline regions fixed. We showed that mechanical properties of these synthetic proteins could be tuned by modulating their molecular weights. Specifically, the toughness and extensibility of synthetic polypeptides increase as a function of the number of tandem repeats. This result suggests that the repetitions in native squid proteins could have a genetic advantage for increased toughness and flexibility.

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