"Swinging" molecule may affect mood

In work that might clarify the process by which proteins fold as well as lead to new approaches to drug development and computer memory, scientists from Purdue University, West Lafayette, Ind., have made an important biological molecule "swing." Using lasers to initiate and probe the folding process, a group, including chemist Timothy Zwier, precisely has determined the energies needed to twist tryptamine, a molecule with several flexible "hinges" that bear a close resemblance to an amino acid, the basis of proteins.

Understanding the energy pathways that these molecules take passing from one conformation to another could provide new understanding of the elusive process of protein folding--an essential part of the development of these fundamental biological molecules. Even though tryptamine forms only a tiny portion of a protein, a clearer picture of this close chemical relative to serotonin and melatonin could provide insights into these other substances' effect on the brain.

"If you want to know how molecules function in the body, you can't just look at their structure--you have to look at the dynamics of how they change," points out Zwier, professor of chemistry in the School of Science. "On a small scale, we have found a way to look at the dynamic processes that make one such molecule change shape. While we're still a long way from understanding how proteins take on their complex shapes, this work could be a step in that direction."

"Ideally," he adds, "we would like to watch a protein being 'born,' as it undergoes the intricate folding process that is needed to give it its final structure. We simply can't do that yet on a molecule as large as a protein, so we decided to examine tryptamine, a simpler molecule that also can fold in several different ways. Our hope is to learn something from it that can carry over to much larger molecules."

The appeal to industry is not as obvious as it might be to fundamental research, but Zwier notes that there is potential for the work to inspire new approaches to problems that are confronting computer data storage.

Zwier also speculates that tryptamine's chemical similarity to serotonin and other mood-related substances could lead to new basic knowledge about their function in the brain. "For serotonin to bond to its receptor in the brain, it must change configuration. More precise knowledge of the energy it must take from its environment could contribute to a better understanding of how serotonin binding in the brain leads to a change in mood."

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