Tryptophan Lyase (NosL): A Cornucopia of 5'-Deoxyadenosyl Radical Mediated Transformations
Dhananjay M Bhandari1, Dmytro Fedoseyenko1, Tadhg P Begley1
1Department of Chemistry, Texas A&M University , College Station, Texas 77843, United States.
Abstract:
Tryptophan lyase (NosL) is a radical S-adenosyl-l-methionine (SAM) enzyme that catalyzes the formation of 3-methyl-2-indolic acid from l-tryptophan. In this paper, we demonstrate that the 5'-deoxyadenosyl radical is considerably more versatile in its chemistry than previously anticipated: hydrogen atom abstraction from Nα-cyclopropyltryptophan occurs at Cα rather than the amino group with NosL Y90A and replacing the substrate amine with a ketone or an alkene changes the chemistry from hydrogen atom abstraction to double bond addition. In addition, the 5'-deoxyadenosyl radical can add to the [4Fe-4S] cluster and dithionite can be used to trap radicals at the active site.
Related Concept Videos
Amino Acid Biosynthetic Pathways
Transcription Attenuation in Prokaryotes
There are several different mechanisms used to attenuate transcription. In ribosome mediated...
Repressible Operon: trp Operon
Spontaneous and Induced Mutations
Transformation
Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase

![Radiosynthesis of 1-2-[18F]Fluoroethyl-L-Tryptophan using a One-pot, Two-step Protocol](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F63025.jpg&w=3840&q=50)
