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Scientists design protein mat that can soak up pollution

Researchers at the University of California, Berkeley, have found a way to enable certain proteins to function and stay active outside of the cell. The groundbreaking study may be the first step toward harnessing the power of proteins in synthetic systems to capture chemical pollution.

Scientists have tried for many years to stabilize proteins outside of their native environments, but there has been little success in merging proteins and synthetic components without compromising protein activity.

The study was led by the lab of co-author Ting Xu, a professor in the Department of Materials Science and Engineering and the Department of Chemistry at Berkeley.

“We think we’ve cracked the code for interfacing natural and synthetic systems,” said Xu.

Proteins do not hold up very well once they are removed from their natural domain. Proteins must maintain a specific folded structure to function properly, and this structure is often supported with the help of other proteins.

In Xu’s lab, the researchers set out to develop a synthetic polymer that could provide a protein with everything it needs to keep its structure.

“Proteins have a very well-defined statistical pattern, so if you can mimic that pattern, then you can marry the synthetic and natural systems, which allows us to make these materials,” said Xu.

The team created random heteropolymers, which they refer to as RHPs. These heteropolymers are made up of four types of monomer subunits, each with chemical properties designed to interact with chemical patches on the surface of proteins.

The RHPs mimicked unstructured proteins, which are commonly found in cells. The experts found that RHPs increased protein folding in water, which means they supported the structure of the protein, and preserved protein activity in organic solvents.

An extensive series of simulations confirmed that RHP could favorably interact with protein surfaces, promoting protein folding and stability in a non-native environment.

The researchers then tested whether they can use an RHP to create protein-based materials for capturing toxic chemicals. The researchers mixed RHP with a protein called organophosphorus hydrolase (OPH), which degrades the toxic organophosphates found in insecticides and in chemical warfare agents.

The RHP/OPH material was used to make fiber mats. Once the mats were submerged in a common insecticide, they degraded an amount of insecticide that weighed about one-tenth of the mat in just a few minutes. The fiber mats could potentially be scaled up to capture a larger amount of toxic chemicals.

“Our study indicated that the approach should be applicable to other enzymes,” said Xu. “This may make it possible to have a portable chemistry lab in different materials.”

The study will be published in the journal Science on March 16.

By Chrissy Sexton, Staff Writer

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