title: YcaO domains use ATP to activate amide backbones during peptide cyclodehydrations.
abstract: Thiazole/oxazole-modified microcins (TOMMs) encompass a recently defined class of ribosomally synthesized natural products with a diverse set of biological activities. Although TOMM biosynthesis has been investigated for over a decade, the mechanism of heterocycle formation by the synthetase enzymes remains poorly understood. Using substrate analogs and isotopic labeling, we demonstrate that ATP is used to directly phosphorylate the peptide amide backbone during TOMM heterocycle formation. Moreover, we present what is to our knowledge the first experimental evidence that the D-protein component of the heterocycle-forming synthetase (YcaO/domain of unknown function 181 family member), formerly annotated as a docking protein involved in complex formation and regulation, is able to perform the ATP-dependent cyclodehydration reaction in the absence of the other TOMM biosynthetic proteins. Together, these data reveal the role of ATP in the biosynthesis of azole and azoline heterocycles in ribosomal natural products and prompt a reclassification of the enzymes involved in their installation.
authors.affiliation: Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA.
authors.forename: Kyle L
authors.initials: KL
authors.lastname: Dunbar
authors.forename: Joel O
authors.initials: JO
authors.lastname: Melby
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Mitchell
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000577:Amides / Q000378:metabolism; D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000096:biosynthesis* / Q000737:chemistry; D001426:Bacterial Proteins / Q000378:metabolism*; D001430:Bacteriocins / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics; D020134:Catalytic Domain; D003500:Cyclization; D006868:Hydrolysis; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000378:metabolism*; D005810:Multigene Family; D010080:Oxazoles / Q000378:metabolism; D010452:Peptide Biosynthesis; D010456:Peptides, Cyclic / Q000096:biosynthesis* / Q000737:chemistry; D010766:Phosphorylation; D013379:Substrate Specificity; D013844:Thiazoles / Q000378:metabolism
chemical_list: D000577:Amides; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001430:Bacteriocins; D009097:Multienzyme Complexes; D010080:Oxazoles; D010456:Peptides, Cyclic; D013844:Thiazoles; C102057:microcin B17 synthase; C020411:microcin; D000255:Adenosine Triphosphate