title: Tryptophan Lyase (NosL): A Cornucopia of 5'-Deoxyadenosyl Radical Mediated Transformations.
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.
authors.affiliation: Department of Chemistry, Texas A&M University , College Station, Texas 77843, United States.
authors.forename: Dhananjay M
authors.identifier: 0000-0003-4250-3303
authors.initials: DM
authors.lastname: Bhandari
authors.affiliation: Department of Chemistry, Texas A&M University , College Station, Texas 77843, United States.
authors.forename: Dmytro
authors.identifier: 0000-0001-7776-8278
authors.initials: D
authors.lastname: Fedoseyenko
authors.affiliation: Department of Chemistry, Texas A&M University , College Station, Texas 77843, United States.
authors.forename: Tadhg P
authors.identifier: 0000-0001-5134-2623
authors.initials: TP
authors.lastname: Begley
mesh_terms: D055162:Biocatalysis; D020134:Catalytic Domain; D005609:Free Radicals / Q000378:metabolism; D008190:Lyases / Q000737:chemistry* / Q000378:metabolism*; D008958:Models, Molecular; D012436:S-Adenosylmethionine / Q000737:chemistry* / Q000378:metabolism*; D014364:Tryptophan / Q000378:metabolism*
chemical_list: D005609:Free Radicals; D012436:S-Adenosylmethionine; D014364:Tryptophan; D008190:Lyases