Science has long taken inspiration from the natural world, and few natural designs are as iconic as the helical shape that makes life possible. The best-known example of such a molecule is DNA, a double helix that carries the genetic instructions for all living organisms. Similar helical shapes are also found in proteins. This shape is special in that it imparts a certain adaptability to biological molecules. For instance, by changing how tightly they twist or even the direction of their twist, biological systems can respond and adapt to their environment. This helps proteins adjust their shapes to fold correctly and perform essential tasks.
Inspired by this design, researchers from Chiba University, Shizuoka University, Keele University, Kanazawa University, and Ritsumeikan University, Japan, have developed a chlorophyll-based supramolecular polymer that can gradually transform from nonhelical fibers into well-defined helical structures over time.
The study was led by Professor Shiki Yagai at the Institute for Advanced Academic Research, Chiba University, along with Balaraman Vedhanarayanan and Ryoma Tsuchida from the Graduate School of Engineering, Chiba University; Shinnosuke Kawai from Shizuoka University; and Martin J. Hollamby at Keele University, UK. The study was published online in the Journal of the American Chemical Society on April 20, 2026.
"Examples of synthetic supramolecular polymers in which multiple helicity arises dynamically from kinetically trapped, nonhelical structures are rare," says Prof. Yagai.
The developed molecule overcomes this limitation. Instead of forming a helix immediately, it evolves step by step, passing through several intermediate stages before reaching its final helical form. It begins as a nonhelical fiber, then develops two loose helices, and finally tightens into a more twisted structure.
The researchers synthesized a chlorophyll derivative functionalized with barbituric acid groups and long alkyl chains. These molecules assemble into ring-like structures called rosettes through hydrogen bonding. In low-polarity solvents, the rosettes stack into long, one-dimensional fibers. The large and complex structure of each chlorophyll unit prevents the rosettes from immediately arranging into a stable configuration. As a result, the system first forms nonhelical fibers, which gradually reorganize into helices with tighter twists over time.
Using atomic force microscopy, the team identified four distinct fiber types: a nonhelical form (NF), in which rosettes are stacked directly without offset, and three helical forms (HF1, HF2, and HF3) that arise from slight translational shifts between stacked rosettes, resulting in twisted structures. All three helices are right-handed but differ in pitch: 26 nm for HF1, 13 nm for HF2, and 8 nm for HF3.
Using advanced imaging techniques, the team then tracked how these structures evolved over time. Starting with a solution dominated by nonhelical fibers, they observed a gradual transformation into helical structures over the course of several days. Within the first 30 minutes, most nonhelical fibers disappeared, giving way to HF1 and HF2. Over the next few hours, HF1 was converted almost entirely into HF2. The final transformation, from HF2 to the most tightly twisted form, HF3, occurred much more slowly, taking several days.
The researchers also found that this transformation occurs cooperatively. Once a small region of a fiber adopts a more stable helical structure, it promotes similar changes in neighboring regions, allowing the transformation to spread along the polymer.
"We demonstrate that helicity in a one-dimensional supramolecular polymer can emerge and mature through discrete, cooperative reorganizations occurring within the polymer backbone across a rugged energy landscape, representing a rare behavior," says Prof. Yagai.
These findings also point to a blueprint for designing dynamic helical structures. By creating molecular building blocks that can adopt multiple stable arrangements with only small energy differences, it may be possible to design materials that change their structure over time in a controlled way.
Looking ahead, the team notes that an important question remains: whether these structural changes occur randomly along the fibers or propagate in a directional manner from specific starting points. Understanding this process could help scientists design materials that more closely mimic the adaptability seen in nature.
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Reference:
DOI: 10.1021/jacs.6c03125
Authors: Balaraman Vedhanarayanan 1,2 , Ryoma Tsuchida 3 , Ryo Kudo 3 , Hiroki Hanayama 1 , Sougata Datta 4 , K. C. Seetha Lakshmi 1 , Hitoshi Tamiaki 5 , Nobuyuki Hara 5,6 , Yuta Hori 7,8 , Sarah E. Rogers 9 , Takatoshi Fujita 10 , Martin J. Hollamby 11,* , Shinnosuke Kawai 12,* , Shiki Yagai 1,4*
Affiliations:
1 Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, Chiba University, Japan
2 Department of Chemistry, Faculty of Engineering and Technology, SRM Institute of Science and Technology, Kattankulathur, Chengalpattu 603 203, Tamil Nadu, India.
3 Division of Advanced Science and Engineering, Graduate School of Science and Engineering, Chiba University, Japan
4 Institute for Advanced Academic Research (IAAR), Chiba University, Japan
5 Graduate School of Life Sciences, Ritsumeikan University, Japan
6 Department of Chemistry, College of Humanities & Sciences, Nihon University, Japan
7 Center for Computational Sciences, University of Tsukuba, Japan
8 Institute of Philosophy in Interdisciplinary Sciences , Kanazawa University, Japan
9 ISIS Pulsed Neutron Source, Rutherford Appleton Laboratory, UK
10 Institute for Quantum Life Science, National Institutes for Quantum Science and Technology (QST), Japan
11 Department of Chemistry, School of Chemical and Physical Sciences, Keele University, UK
12 Department of Chemistry, Faculty of Science, Shizuoka University, Japan
About Professor Shiki Yagai
Professor Shiki Yagai is a well-established researcher at Chiba University, Japan. In 2002, he received his Ph.D. from Ritsumeikan University, Japan. He joined Chiba University as an Assistant Professor and was promoted to full-time professor in 2017. He has authored over 200 publications in the fields of molecular self-assembly, supramolecular polymers, and functional dyes, with a focus on nanostructural control. He leads the Grant-in-Aid for Transformative Research Areas (A) project titled "Materials Science of Meso-Hierarchy," which spans from 2023 to 2027. This project focuses on exploring the hierarchical structures of materials to develop innovative functional materials at the mesoscopic scale.
Funding:
This work was supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI (grant numbers: 22H00331, 23K19237, and 23H04873) under the Grant-in-Aid for Transformative Research Areas "Materials Science of Meso-Hierarchy." It also used the SasView application, originally developed under NSF award DMR-0520547 and further supported by the European Union's Horizon 2020 research and innovation program through the SINE2020 project (grant number: 654000).
Journal of the American Chemical Society
Experimental study
Not applicable
Sequential, Multistep, and Cooperative Helicity Evolution in Supramolecular Polymers of Chlorophyll Rosettes
20-Apr-2026
The authors declare no competing financial interests.