title: Structure of Ddn, the deazaflavin-dependent nitroreductase from Mycobacterium tuberculosis involved in bioreductive activation of PA-824.
abstract: Tuberculosis continues to be a global health threat, making bicyclic nitroimidazoles an important new class of therapeutics. A deazaflavin-dependent nitroreductase (Ddn) from Mycobacterium tuberculosis catalyzes the reduction of nitroimidazoles such as PA-824, resulting in intracellular release of lethal reactive nitrogen species. The N-terminal 30 residues of Ddn are functionally important but are flexible or access multiple conformations, preventing structural characterization of the full-length, enzymatically active enzyme. Several structures were determined of a truncated, inactive Ddn protein core with and without bound F(420) deazaflavin coenzyme as well as of a catalytically competent homolog from Nocardia farcinica. Mutagenesis studies based on these structures identified residues important for binding of F(420) and PA-824. The proposed orientation of the tail of PA-824 toward the N terminus of Ddn is consistent with current structure-activity relationship data.
authors.affiliation: Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121-1125, USA.
authors.forename: Susan E
authors.initials: SE
authors.lastname: Cellitti
authors.forename: Jennifer
authors.initials: J
authors.lastname: Shaffer
authors.forename: David H
authors.initials: DH
authors.lastname: Jones
authors.forename: Tathagata
authors.initials: T
authors.lastname: Mukherjee
authors.forename: Meera
authors.initials: M
authors.lastname: Gurumurthy
authors.forename: Badry
authors.initials: B
authors.lastname: Bursulaya
authors.forename: Helena I
authors.initials: HI
authors.lastname: Boshoff
authors.forename: Inhee
authors.initials: I
authors.lastname: Choi
authors.forename: Amit
authors.initials: A
authors.lastname: Nayyar
authors.forename: Yong Sok
authors.initials: YS
authors.lastname: Lee
authors.forename: Joseph
authors.initials: J
authors.lastname: Cherian
authors.forename: Pornwaratt
authors.initials: P
authors.lastname: Niyomrattanakit
authors.forename: Thomas
authors.initials: T
authors.lastname: Dick
authors.forename: Ujjini H
authors.initials: UH
authors.lastname: Manjunatha
authors.forename: Clifton E
authors.initials: CE
authors.lastname: Barry
authors.forename: Glen
authors.initials: G
authors.lastname: Spraggon
authors.forename: Bernhard H
authors.initials: BH
authors.lastname: Geierstanger
mesh_terms: D000595:Amino Acid Sequence; D005415:Flavins / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D016296:Mutagenesis; D009169:Mycobacterium tuberculosis / Q000201:enzymology*; D009593:Nitroimidazoles / Q000378:metabolism; D009601:Nitroreductases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D026361:Reactive Nitrogen Species / Q000378:metabolism
chemical_list: D005415:Flavins; D009593:Nitroimidazoles; D026361:Reactive Nitrogen Species; C019319:5-deazaflavin; D009601:Nitroreductases