Molecular motors power life – and perhaps future technology too
Amolecular motor is a molecule or molecular complex that converts energy into directed motion and performs work. Such motors are widespread in nature and carry out many functions essential to life in cells.
One of the best-known molecular motorsis ATP synthase. It is an enzyme complex located in the cell membrane of bacteria and in the inner mitochondrial membrane in humans.
ATP synthase is a fine example of how cells use motion to produce energy.
“Molecular motors are nature’s own nanomachines that enable numerous functions essential to life, such as transporting substances and using energy in cells,” says Postdoctoral Researcher Petteri Vainikka from the Department of Chemistry at the University of Jyväskylä.
ATP synthase works like a nanoscale turbine: the difference in proton (hydrogen ion) concentration across the membrane causes protons to flow through the motor, making its rotor turn. Through this rotational motion, ATP synthase produces ATP, which serves as a key carrier of chemical energy in the cell.
Alongside natural motors, researchers have also developed synthetic molecular motors. These organic molecules are considerably smaller than their biological counterparts, and their motion can be controlled using electrical impulses, ultraviolet light or visible light, for example.
Researchers take inspiration from natural molecular motors
At JYU, Vainikka studies nature’s own molecular motors, particularly ATP synthase. In his research, he uses advanced computer simulations to examine phenomena that are difficult or even impossible to observe experimentally.
“Natural molecular motors are extremely complex. Simulations allow us to identify what is essential to a phenomenon. Once we understand the mechanisms in sufficient detail, we can also test them experimentally later,” says Vainikka.
The long-term aim is to learn from nature:
Nature provides us with a recipe book. Once we understand how natural molecular motors work, we can try to build new synthetic solutions based on them.”
Vainikka brings expertise from the University of Groningen, where he developed and applied the Martini simulation method to human-made molecular motors, among other things. The method omits some atomic-level details, allowing the behaviour of large molecular systems to be monitored over considerably longer timescales and larger sizes than in traditional simulations.
Molecular motors for technology and biomaterials
The long-term aim of molecular motor research is not only to understand motion at the nanoscale but also to make use of it in new technologies.
If we learn to design molecular motors based on nature’s operating principles and control their motion precisely, we may be able to use them in entirely new applications in biotechnology, medicine and nanotechnology,” says Vainikka.
Researchers have already shown that molecular motors can be incorporated into biomaterials. Their motion can then cause the material to contract like muscle tissue or influence how cells behave in their environment.
Vainikka was involved in a study in which light-driven molecular motors were attached to a surface used for growing mesenchymal stem cells (derived from embryonic connective tissue). Activating the motors affected cell differentiation, and computer simulations were used to investigate how this effect might be transmitted to the cells through proteins attached to the surface.
“Observing a change in a cell does not yet tell us what caused it. Simulations allow us to isolate individual interactions and assess whether a proposed molecular-level mechanism can explain an experimental observation,” Vainikka explains.
From a passion for science fiction to an international research career
Vainikka’s interest in molecular machines goes back to his childhood.
As a child, I became fascinated by early-2000s science fiction, in which nanotechnology and nanomachines played a central role. Even then, I was captivated by the idea of extremely tiny machines.”
The researcher’s path has not been straightforward, however. Vainikka began studying geology at the University of Turku but later moved on to materials chemistry. He became fascinated by computational chemistry, particularly nanoscale machines such as molecular switches and molecular motors.
Vainikka completed his doctoral dissertation at the University of Groningen, after which he worked as a Wenner-Gren Postdoctoral Fellow at Lund University. In his research on molecular motors, he also collaborated with the research group of Ben Feringa, a Nobel laureate in Chemistry. When a position became available in Professor Gerrit Groenhof’s research groupat the University of Jyväskylä, the decision was easy.
“I had followed Gerrit’s research for a long time. When I saw the vacancy, it felt as though the position had been made just for me,” says Vainikka.
Curiosity drives a researcher’s career
According to Vainikka, his motivation for doing research remains the same as it was at the beginning of his career: a desire to understand how the world works.
“My curiosity is almost pathological. If we learn to understand exactly how these tiny machines work, we can enable entirely new kinds of technology. But it is equally important that we find answers to fundamental questions about nature,” says Vainikka.
