title: Enzyme inhibition by hydroamination: design and mechanism of a hybrid carmaphycin-syringolin enone proteasome inhibitor.
abstract: Hydroamination reactions involving the addition of an amine to an inactivated alkene are entropically prohibited and require strong chemical catalysts. While this synthetic process is efficient at generating substituted amines, there is no equivalent in small molecule-mediated enzyme inhibition. We report an unusual mechanism of proteasome inhibition that involves a hydroamination reaction of alkene derivatives of the epoxyketone natural product carmaphycin. We show that the carmaphycin enone first forms a hemiketal intermediate with the catalytic Thr1 residue of the proteasome before cyclization by an unanticipated intramolecular alkene hydroamination reaction, resulting in a stable six-membered morpholine ring. The carmaphycin enone electrophile, which does not undergo a 1,4-Michael addition as previously observed with vinyl sulfone and α,β-unsaturated amide-based inhibitors, is partially reversible and gives insight into the design of proteasome inhibitors for cancer chemotherapy.
authors.affiliation: Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA 92093-0212, USA; Institute of Chemistry, University of Campinas, Campinas SP 13083-970, Brazil; Brazilian Biosciences National Laboratory, National Center for Research in Energy and Materials, Campinas SP 13083-970, Brazil.
authors.forename: Daniela B B
authors.initials: DB
authors.lastname: Trivella
authors.affiliation: Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA 92093-0212, USA.
authors.forename: Alban R
authors.initials: AR
authors.lastname: Pereira
authors.affiliation: Center for Integrated Protein Science, Department Chemie, Lehrstuhl für Biochemie, Technische Universität München, Garching 85747, Germany.
authors.forename: Martin L
authors.initials: ML
authors.lastname: Stein
authors.affiliation: Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA 92093-0212, USA.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kasai
authors.affiliation: Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA 92093-0212, USA.
authors.forename: Tara
authors.initials: T
authors.lastname: Byrum
authors.affiliation: Henry Ford Health System, Department of Internal Medicine, Josephine Ford Cancer Center, 440 Burroughs, Detroit, MI 48202, USA.
authors.forename: Frederick A
authors.initials: FA
authors.lastname: Valeriote
authors.affiliation: Department of Chemistry, University of California at Davis, 1 Shields Avenue, Davis, CA 95616, USA.
authors.forename: Dean J
authors.initials: DJ
authors.lastname: Tantillo
authors.affiliation: Center for Integrated Protein Science, Department Chemie, Lehrstuhl für Biochemie, Technische Universität München, Garching 85747, Germany. Electronic address: michael.groll@tum.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Groll
authors.affiliation: Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA 92093-0212, USA; Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, La Jolla, CA 92093-0736, USA. Electronic address: wgerwick@ucsd.edu.
authors.forename: William H
authors.initials: WH
authors.lastname: Gerwick
authors.affiliation: Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA 92093-0212, USA; Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, La Jolla, CA 92093-0736, USA. Electronic address: bsmoore@ucsd.edu.
authors.forename: Bradley S
authors.initials: BS
authors.lastname: Moore
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D000586:Amination; D000970:Antineoplastic Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D055162:Biocatalysis; D001688:Biological Products / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D003500:Cyclization; D004151:Dipeptides / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D045325:HCT116 Cells; D006801:Humans; D007659:Ketones / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D010456:Peptides, Cyclic / Q000737:chemistry*; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D061988:Proteasome Inhibitors / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D011789:Quantum Theory; D013329:Structure-Activity Relationship
chemical_list: D000475:Alkenes; D000970:Antineoplastic Agents; D001688:Biological Products; D004151:Dipeptides; D007659:Ketones; D010456:Peptides, Cyclic; D061988:Proteasome Inhibitors; D046988:Proteasome Endopeptidase Complex