Folded peptides conduct electricity better than unfolded counterparts

Researchers at the Beckman Institute for Advanced Science and Technology have made a groundbreaking discovery, finding that folded peptides are more electrically conductive than their unfolded counterparts. This breakthrough was achieved through an interdisciplinary approach combining single-molecule experiments, molecular dynamics simulations, and quantum mechanics. Led by Charles Schroeder, the James Economy Professor in Materials Science and Engineering at the University of Illinois Urbana-Champaign, the team’s findings have significant implications for the design and development of more efficient molecular electronic devices.

The study focused on peptides, fragments of proteins with a fraction of the amino acids, and found that their folded secondary structure enabled better electron transport than their stretched-out primary structure. Rajarshi “Reeju” Samajdar, a graduate student in the Schroeder Group, conducted single-molecule experiments to observe this phenomenon, while Moeen Meigooni, a graduate research assistant, used computer modeling to simulate the peptides’ conformational behavior. The team’s results have far-reaching potential for applications in molecular electronic devices like semiconductors that work by switching between two distinct structures.

Electron Transport in Peptides: Unraveling the Role of Structure

The intricate dance of electrons within living cells is a crucial process that enables essential biological functions such as photosynthesis and respiration. A recent study published in the Proceedings of the National Academy of Sciences has shed new light on the role of peptide structure in facilitating electron transport, a discovery with significant implications for the design and development of molecular electronic devices.

The Importance of Peptide Structure

Peptides, fragments of proteins comprising a few amino acids, have been found to exhibit enhanced electrical conductivity when folded into a specific secondary structure. This finding contrasts with their unfolded primary structure, which displays reduced conductivity. The research team, led by Charles Schroeder, employed an interdisciplinary approach combining single-molecule experiments, molecular dynamics simulations, and quantum mechanics to validate their results.

The significance of peptide structure in electron transport lies in its ability to modulate the flow of electrons. Proteins, which are integral to cellular activities, reside in all living cells and are composed of long sequences of amino acids. The primary structure of a protein is a linear sequence of amino acids, whereas the secondary structure arises from interactions between these amino acids, leading to a collapsed or folded conformation.

Investigating Peptide Conductivity

Rajarshi “Reeju” Samajdar, a graduate student in the Schroeder Group, conducted single-molecule experiments on peptides with approximately four or five amino acids. This allowed for more granular observation of the peptide’s behavior and revealed a surprising difference in conductivity between the folded and unfolded states.

To verify these observations, the researchers employed molecular dynamics simulations to model the conformational behavior of the peptides. The results confirmed the distinct structural shifts observed by Samajdar. Furthermore, quantum mechanical calculations were used to confirm that the changes in conductivity were indeed linked to the two discrete structures.

Implications for Molecular Electronic Devices

The discovery that folded peptides exhibit enhanced electrical conductivity has significant implications for the design and development of molecular electronic devices. The specific secondary structure observed in this study, known as the 310 helix, may be exploited to create semiconductors that switch between two distinct structures, enabling more efficient electron transport.

The interdisciplinary approach employed by the research team highlights the importance of collaboration in advancing our understanding of complex biological processes and their potential applications. As Moeen Meigooni, a graduate research assistant, noted, “Beckman’s interdisciplinary structure allowed for this collaboration to happen in the first place… This discovery didn’t come from a grant that we planned together. It was actually pretty spontaneous.”

Future Directions

The findings of this study pave the way for further investigations into the role of peptide structure in electron transport and its potential applications in molecular electronic devices. The development of more efficient semiconductors could have significant implications for fields such as energy storage and conversion.

Moreover, this research highlights the importance of interdisciplinary approaches in advancing our understanding of complex biological processes and their potential applications. As scientists continue to unravel the intricacies of electron transport in peptides and proteins, we may uncover new opportunities for innovation and discovery.