Advertisement

If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.

ENJOY UNLIMITED ACCES TO C&EN

Materials

Unexpected Route To Crystallization

Electrostatic repulsion between peptide-alkyl chain fibers in dilute solution leads to 3-D ordering

by Mitch Jacoby
December 21, 2009 | A version of this story appeared in Volume 87, Issue 51

[+]Enlarge
Credit: Courtesy of Samuel Stupp
Electrostatic repulsions drive crystallization in networks of the peptide-based filaments shown in this electron micrograph.
Credit: Courtesy of Samuel Stupp
Electrostatic repulsions drive crystallization in networks of the peptide-based filaments shown in this electron micrograph.

Long-range electrostatic repulsion can drive crystallization in three-dimensional networks of like-charged peptide-based filaments, according to a study from Northwestern University (Science, DOI: 10.1126/science.1182340). The unprecedented crystallization mechanism could play a previously unrecognized role in forming cytoskeletal structures—the protein “scaffolding” in cells—and lead to advances in biomedical applications. Honggang Cui, Samuel I. Stupp, and coworkers report that a synthetic molecule made from a peptide sequence grafted to an alkyl chain spontaneously forms networks of cylindrical fibers. These filaments consist of a hydrocarbon core and peptide periphery that are roughly 10 nm in diameter and estimated to be at least tens of micrometers in length. In dilute solutions of about 1 wt % or higher, repulsion between negatively charged nanofibers causes the structures to crystallize spontaneously. In less concentrated solutions, deprotonation stimulated by X-rays triggers reversible crystallization, leading to ordered fiber bundles with interfiber separations of up to 320 Å. That distance is on the order of 10 times the range of values reported for cytoskeleton filaments and DNA strands, the team says.

Article:

This article has been sent to the following recipient:

0 /1 FREE ARTICLES LEFT THIS MONTH Remaining
Chemistry matters. Join us to get the news you need.