Arginine tango
As a means to evade the host immune response, S. aureus uses an enzyme called oleate hydratase, or OhyA, to inactivate antimicrobial unsaturated fatty acids in the membrane that would otherwise inhibit bacterial growth. Research scientists at St. Jude Children’s Research Hospital reported today the structure and catalytic mechanism of OhyA.
Christopher Radka of St. Jude’s Department of Infectious Diseases describes the research during a presentation Tuesday at 2 p.m. EDT at the 2021 ASBMB Annual Meeting, held in conjunction with the Experimental Biology conference.
Radka and colleagues used X-ray crystallography to determine the structure of OhyA. Solving and evaluating multiple OhyA crystal structures highlighted a coordinated dance that occurs between key arginine residues and the unsaturated fatty acid substrate in the active site of the enzyme, a process facilitated by the nucleotide cofactor FAD.
In this dance, the substrate is first guided into the binding tunnel by the oleate carbonyl of OhyA, then encounters its first arginine dance partner (Arg81) at the entrance of the active site. FAD binding then triggers the rotation of Arg81 that guides the fatty acid as it curls into the active site. After catalysis, a second arginine (Arg78) rotates behind the fatty acid carboxyl to release the hydroxylated product from the active site.
“What’s novel about the (active site) is how these conserved arginines guide the substrate through the donut-shaped active site,” Radka said. “Here, the arginines dance like two partners in a tango.”
This highly choreographed dance controls how the fatty acid substrate moves into and out of the active site. “In this coordinated tango at the active site, the FAD is the dramatic third character whose role is to come in and advance the dance so the chemistry can occur,” Radka said.
In this reaction, FAD remains oxidized and unconsumed. This quality is advantageous for industrial biotechnology research looking to use OhyA; FAD-dependent reactions often consume FADH2 and require continued starting product, which can be costly.
Future goals for this research include determining the structural elements required for S. aureus OhyA to remove antimicrobial fatty acids from the membrane.
Enjoy reading ASBMB Today?
Become a member to receive the print edition four times a year and the digital edition weekly.
Learn moreGet the latest from ASBMB Today
Enter your email address, and we’ll send you a weekly email with recent articles, interviews and more.
Latest in Science
Science highlights or most popular articles
Guiding grocery carts to shape healthy habits
Robert “Nate” Helsley will receive the Walter A. Shaw Young Investigator in Lipid Research Award at the 2025 ASBMB Annual Meeting, April 12–15 in Chicago.
Quantifying how proteins in microbe and host interact
“To develop better vaccines, we need new methods and a better understanding of the antibody responses that develop in immune individuals,” author Johan Malmström said.
Leading the charge for gender equity
Nicole Woitowich will receive the ASBMB Emerging Leadership Award at the 2025 ASBMB Annual meeting, April 12–15 in Chicago.
CRISPR gene editing: Moving closer to home
With the first medical therapy approved, there’s a lot going on in the genome editing field, including the discovery of CRISPR-like DNA-snippers called Fanzors in an odd menagerie of eukaryotic critters.
Finding a missing piece for neurodegenerative disease research
Ursula Jakob and a team at the University of Michigan have found that the molecule polyphosphate could be what scientists call the “mystery density” inside fibrils associated with Alzheimer’s, Parkinson’s and related conditions.
From the journals: JLR
Enzymes as a therapeutic target for liver disease. Role of AMPK in chronic liver disease Zebrafish as a model for retinal dysfunction. Read about the recent JLR papers on these topics.