Symmetry model sheds light on chemistry surrounding peptide helices

Helices are structures that occur naturally in many important molecules, such as proteins. These helices have a twist that depends on the arrangement of their building blocks. By understanding how a helix forms, we can better understand how these structures influence the behavior of proteins in our bodies.

In peptides, which are small fragments of proteins, their helical shape results from the repetition of specific blocks called amino acids. These units can be arranged to create a new chiral layer, adopting a particular orientation that affects the properties of the peptide. Chirality therefore plays a crucial role in how these molecular structures are organized and function.

A study published in Nature Communications explores this new layer of chiral information that can be generated in the alpha-helical conformations of peptides.

By examining the different types of helices that can form, the authors have described, for the first time, a symmetry model that improves our understanding of their relationships. Led by Dr. Julián Bergueiro of the Centre for Biological Chemistry and Molecular Materials (CiQUS), the study details how different amino acid sequences influence the arrangement and properties of these helical structures.

To achieve this, the team used computational techniques and circularly polarized light spectroscopy, a method suited to analyzing how molecules interact with chiral light. This approach allowed them to characterize various exohelical topologies that precisely matched theoretical predictions.

“The results showed that different patterns or ways of repeating amino acids lead to distinct helical structures. This is essential for understanding how many proteins carry out their biological activities and offers potential for designing new molecules for applications in medicine, biotechnology or for new biocompatible materials,” explains Bergueiro.

Controlling the monomer sequence would allow the design of specific topologies along the polymer chain, representing a new approach in macromolecular engineering. This study marks a significant advance in the field of peptide chemistry, transforming our understanding of how helical structures can potentially be exploited in the development of new compounds and technologies.