Radical <i>S</i>-adenosyl-L-methionine (SAM) enzymes, one of the largest enzyme superfamilies, utilize a [4Fe-4S] cluster and SAM to generate a 5’-deoxyadenosyl radical (5’-dAdo●). This highly reactive species goes on to catalyze a wide range of reactions including sulfur insertion, methylation, rearrangement, and many others in a variety of biological systems. Lysine-2,3-aminomutase (LAM) is a radical SAM enzyme that catalyzes the rearrangement of α-lysine to b-lysine. This reaction is essential because b-lysine is a precursor to the antibiotics viomycin and streptothricin. Unlike some other radical SAM enzymes, such as pyruvate formate lyase-activating enzyme (PFL-AE), LAM uses SAM as a cofactor instead of a cosubstrate. Researchers have previously captured an intermediate of the radical SAM enzyme PFL-AE, which stabilizes the 5’-dAdo●. We seek to gain insight into the catalytic mechanism of LAM by capturing one of its intermediates and comparing this to the previous spectroscopically observed PFL-AE intermediate. We are looking to capture the intermediate using rapid freeze quench (RFQ) and then observe it spectroscopically using electron paramagnetic resonance (EPR) spectroscopy. We hope this research will provide insight into the mechanism of how this radical species is controlled by the protein environment to minimize radical proliferation in a biological context.

Capturing an intermediate of the radical <i>S</i>-adenosyl-L-methionine enzyme lysine 2,3-aminomutase

253rd National Meeting (2017)

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Capturing an intermediate of the radical S-adenosyl-L-methionine enzyme lysine 2,3-aminomutase