As research laboratories on campuses across the US slowed down in March in response to stay-at-home orders, Northwestern’s Recombinant Protein Production Core (rPPC), a Chemistry of Life Processes Institute-affiliated core facility, was running at full speed.
In response to the urgent cry for new treatments and vaccines to slow the spread of the SARS CoV-2 virus, Sergii Pshenychnyi, Managing Director of the rPPC, flew into production mode. His number one customer—Northwestern’s Center for Structural Genomics of Infectious Diseases (CSGID)—required his services for purification of the virus’s proteins. The Center was acting upon a direct request from the National Institute of Allergy and Infectious Diseases (NIAID), led by Anthony Fauci, MD, for structural studies of SARSCo-V2 proteins.
“If there was ever a time to redirect your research towards a pathogen that, frankly, we as a civilization of the planet have never seen before— this was it,” says Michael Jewett, the Walter P. Murphy Professor of Chemical and Biological Engineering, Director of the Center for Synthetic Biology, and Co-Director of the rPPC.
An important first step in defeating any virus is mapping its protein structure. Proteins provide an entryway for the virus to invade the body by modifying its genetic material so it can hide from the immune system and safely multiply. Defining the 3-D structure of a virus allows drug developers to identify inhibitors that block their action or to search for drugs already approved by the FDA that could work against them.
SARS-CoV-2 is comprised of dozens of continually mutating proteins. Scientists need to understand and track the differences of not only the initial variants of the proteins, but also the mutated variants as well.
“We need lots of protein structure information to develop new therapies,” says Karla Satchell, a microbiologist in the Feinberg School of Medicine, and the head of CSGID, an international consortium of eight institutions funded by the National Institute of Health, that uses protein crystallization to investigate the structures of emerging infectious agents. “We reach out to Sergii for difficult proteins on a regular basis.”
Satchell enlisted Pshenychnyi to produce and purify two proteases central to the function of the virus that are considered likely candidates for drug targets: the SARS-CoV-2 papain-like protease (PLpro) and chymotrypsin-like protease (3CLpro).
“Usually projects like these take two weeks at minimum, but I did it in four days,” said Pshenychnyi who says the high-stakes project triggered a rush of adrenaline. “As soon I produced the protein, CSGID was there within 15 minutes to package it up and FedEx it to Purdue.”
Investigators at Purdue University, a key CSGID collaborating institution, then were able to process the protein material into crystals and use powerful x-rays to analyze the protein’s structure. In record time, they were able to inform the NIAID that none of the existing HIV treatments would be effective against SARS-CoV-2, but that certain Hepatitis C drugs looked promising. To date, the center is responsible for solving about one third of all SARS-CoV-2 protein structures globally.
“This was a major role,” says Satchell, “because these viral protease inhibitors for HIV and HCV were being used in the clinics without any evidence that they would work.”
“We need to have as many shots on goal as we can. Sergii is one of these people that can multitask and get many shots on goal very quickly,” says Jewett. “He has put in tireless hours directing the research efforts of the rPPC to address this pandemic.”
Jewett likens Pshenychnyi’s skill to that of a famous chef running a five-star Michelin restaurant.
“Some people just technically have the secret sauce in their hands. Sergii is an excellent chef of essentially making these proteins,” says Jewett. “There is somewhat of an art form to it and Sergii has that.”
by Lisa La Vallee