Chemists show that nature could have used different protein building blocks

Feb 05, 2007
Beta-Bundles -- Ribbon Diagram Representations of a Beta-Peptide Bundle
Beta-Bundles: Ribbon diagram representations of a beta-peptide bundle illustrating packing between helices and within the hydrophobic (green) core. Credit: Schepartz/Yale

Chemists at Yale have done what Mother Nature chose not to — make a protein-like molecule out of non-natural building blocks, according to a report featured early online in the Journal of the American Chemical Society.

Nature uses alpha-amino acid building blocks to assemble the proteins that make life as we know it possible. Chemists at Yale now report evidence that nature could have used a different building block – beta-amino acids — and show that peptides assembled from beta-amino acids can fold into structures much like natural protein.

Beta-Bundles -- Ribbon Diagram Representations of a Beta-Peptide Bundle
Beta-Bundles: Ribbon diagram representations of a beta-peptide bundle illustrating packing between helices and within the hydrophobic (green) core. Credit: Schepartz/Yale

"The x-ray structure featured in the report shows a molecule that shares many of the structural characteristics of natural proteins," said principal author Alanna Schepartz, the Milton Harris '29 Ph.D. Professor of Chemistry at Yale and a Howard Hughes Medical Institute Professor. "Related studies show that the physical properties of the molecule are also remarkably similar to natural proteins. In other words, the beta-peptide assembly looks and acts a lot like a real protein."

The ability to mimic natural proteins makes beta-peptides powerful new tools for basic research and drug discovery. Like a taped recording, their greatest value may be in their difference from a live performance.

"Since beta-peptides are not processed in the cell like natural peptides or proteins, it may be possible in the future to design beta-peptides that perform better or in more locations than current protein drugs," said Schepartz. "They also may have unique properties as biomaterials."

Natural proteins are composed of linear chains of alpha-amino acids. Beta-peptides are composed of beta-amino acids, which have an extra carbon in their backbone. Like alpha-amino acids, beta-amino acids are generated under simulated pre-biotic conditions, are isolated from meteorites, and are byproducts of metabolism, but they are not genetically encoded like natural proteins, nor are they built into chains by cells.

Since the early 1990's, scientists have been able to assemble beta-peptides into isolated helices. Until now, however, creating a structure that mimics the larger size and complex folded architecture of a natural protein had been an elusive goal. Schepartz's team solved the dilemma by designing a molecule that could form a bundle using characteristics found in natural proteins — a greasy interior that repels water and a water-friendly exterior. This paper, which provides the first high-resolution picture of such a structure, shows a bundle of eight beta-peptides.

"The structure we see is intriguing, as it suggests that natural proteins could have been composed of beta-amino acids, but were not chosen to do so," said Schepartz.

Citation: J. American Chemical Society, ASAP Article DOI:10.1021/ja068678n (January 19, 2007)

Source: Yale University

Explore further: New method allows for greater variation in band gap tunability

add to favorites email to friend print save as pdf

Related Stories

Fish catch break on world stage at global conference

Jan 27, 2015

Inland fishing - the powerful yet quieter sister to the large, salty marine aquaculture powerhouse - has gained what experts say is a much-needed visibility boost this as the first partnership between Michigan ...

Sonic booms in nerves and lipid membranes

Jan 20, 2015

(Phys.org)—Neurons might not be able to send signals as fast as electrons in wires or photons in fiber, but what if they can communicate using miniature sonic booms? That would be quite a revolutionary ...

Recommended for you

Pinholes are pitfalls for high performance solar cells

Jan 30, 2015

The most popular next-generation solar cells under development may have a problem – the top layer is full of tiny pinholes, researchers at the Okinawa Institute of Science and Technology Graduate University ...

Chemistry in a trillionth of a second

Jan 30, 2015

Chemists at the University of Bristol, in collaboration with colleagues at the Central Laser Facility at the Rutherford Appleton Laboratory (RAL) and Heriot-Watt University (HWU), can now follow chemical ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.