UT researchers have developed a new technique called SUpercharged PRotein Assembly (SuPrA), which can combine individual proteins to construct molecular structures and synthetic products.
SuPrA can efficiently mimic the human body’s natural process of making larger molecular structures out of separate proteins, said Anna Simon, a postdoctoral molecular biosciences researcher. The work, which was conducted in collaboration with researchers from the University of Michigan, was published in the online science journal Nature Chemistry.
“The human body uses (protein structures) in many ways, such as cellular communication,” Simon said. “They can also be used to make microtubules, which are protein structures that provide shape to (the body of the cell).”
The technique relies on the attraction between positive and negative charges, Simon said.
“(Through SuPrA), one protein is positively charged and the other negatively charged,” Simon said. “The opposing charges create an attraction between the two proteins, causing them to join together. By using opposing charges, (SuPrA) can assemble proteins that may not naturally interact with each other.”
SuPrA is an inexpensive technique because there are well-established methods for supercharging proteins and the proteins that are used already exist, Simon said. Previous methods relied on artificial designs of proteins.
“One common way is to computationally design proteins that can interact, which can then be produced in labs,” Simon said. “It is a powerful technique but requires (a) lot of specialized skills and designing time.”
To demonstrate how SuPrA works, Simon and her team used green fluorescence protein, a protein that glows green when fluorescent light is shined on it.
“GFP proteins don’t naturally interact with each other,” Simon said. “To check if the two proteins would join together, some green fluorescence protein proteins were modified to fluoresce blue. Then, the (green and blue fluorescent proteins) were supercharged to be positive or negative and allowed to interact.”
The study’s senior author, David Taylor said the proteins assembled together in a ring-shaped structure.
SuPrA can be applied in different fields. For example, it can be used to make structures capable of energy transfer, Simon said.
“We are exploring how SuPrA can build materials that contain proteins capable of harvesting and transferring light energy,” Simon said. “These materials could function like a solar cell, capturing light energy and storing it in a battery.”
SuPrA also can be used in the medical field to design protein structures that can detect chemical signals in the body or to deliver medicine, Simon said.
“Such structures could be used for medical diagnoses such as detecting cancer,” Simon said. “The protein structure would carry medicine into the body and then release it when they meet certain chemical signals.”
The research team is currently exploring SuPrA’s potential to build specialized materials, Simon said.
“With its ability to join proteins, SuPrA could make tough lightweight materials or transparent ones,” Simon said. “These materials would be environmentally friendly since they are designed from proteins.”
Ultimately, the team hopes SuPrA can be used like a 3D printer, said Taylor, molecular biology assistant professor.
“Through SuPrA, proteins can be assembled to build various structures for various purposes,” Taylor said. “We hope that SuPrA can have a wide spread use … joining together proteins to make structures for various uses.”
