title: Mechanism of Inactivation of GABA Aminotransferase by (E)- and (Z)-(1S,3S)-3-Amino-4-fluoromethylenyl-1-cyclopentanoic Acid.
abstract: When γ-aminobutyric acid (GABA), the major inhibitory neurotransmitter in the mammalian central nervous system, falls below a threshold level, seizures occur. One approach to raise GABA concentrations is to inhibit GABA aminotransferase (GABA-AT), a pyridoxal 5'-phosphate-dependent enzyme that degrades GABA. We have previously developed (1S,3S)-3-amino-4-difluoromethylene-1-cyclopentanoic acid (CPP-115), which is 186 times more efficient in inactivating GABA-AT than vigabatrin, the only FDA-approved inactivator of GABA-AT. We also developed (E)- and (Z)-(1S,3S)-3-amino-4-fluoromethylenyl-1-cyclopentanoic acid (1 and 2, respectively), monofluorinated analogs of CPP-115, which are comparable to vigabatrin in inactivating GABA-AT. Here, we report the mechanism of inactivation of GABA-AT by 1 and 2. Both produce a metabolite that induces disruption of the Glu270-Arg445 salt bridge to accommodate interaction between the metabolite formyl group and Arg445. This is the second time that Arg445 has interacted with a ligand and is involved in GABA-AT inactivation, thereby confirming the importance of Arg445 in future inactivator design.
authors.affiliation: Departments of Chemistry and Molecular Biosciences, Chemistry of Life Processes Institute, and the Center for Molecular Innovation and Drug Discovery, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Hyunbeom
authors.initials: H
authors.lastname: Lee
authors.affiliation: Departments of Chemistry and Molecular Biosciences, Chemistry of Life Processes Institute, and the Center for Molecular Innovation and Drug Discovery, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Hoang V
authors.initials: HV
authors.lastname: Le
authors.affiliation: Department of Chemistry and Biochemistry, Loyola University Chicago , Chicago, Illinois 60660, United States.
authors.forename: Rui
authors.initials: R
authors.lastname: Wu
authors.affiliation: Departments of Chemistry and Molecular Biosciences, and the Proteomics Center of Excellence, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Emma
authors.initials: E
authors.lastname: Doud
authors.affiliation: X-ray Science Division, Advanced Photon Source, Argonne National Laboratory , Lemont, Illinois 60439, United States.
authors.forename: Ruslan
authors.initials: R
authors.lastname: Sanishvili
authors.affiliation: Departments of Chemistry and Molecular Biosciences, and the Proteomics Center of Excellence, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: John F
authors.initials: JF
authors.lastname: Kellie
authors.affiliation: Departments of Chemistry and Molecular Biosciences, and the Proteomics Center of Excellence, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Phillip D
authors.initials: PD
authors.lastname: Compton
authors.affiliation: Departments of Chemistry and Molecular Biosciences, Chemistry of Life Processes Institute, and the Center for Molecular Innovation and Drug Discovery, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Boobalan
authors.initials: B
authors.lastname: Pachaiyappan
authors.affiliation: Department of Chemistry and Biochemistry, Loyola University Chicago , Chicago, Illinois 60660, United States.
authors.forename: Dali
authors.initials: D
authors.lastname: Liu
authors.affiliation: Departments of Chemistry and Molecular Biosciences, and the Proteomics Center of Excellence, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Neil L
authors.initials: NL
authors.lastname: Kelleher
authors.affiliation: Departments of Chemistry and Molecular Biosciences, Chemistry of Life Processes Institute, and the Center for Molecular Innovation and Drug Discovery, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Richard B
authors.initials: RB
authors.lastname: Silverman
mesh_terms: D000612:4-Aminobutyrate Transaminase / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D018360:Crystallography, X-Ray; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D008958:Models, Molecular; D011392:Proline / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D013552:Swine
chemical_list: C519726:(1S,3S)-3-amino-4-difluoromethylenecyclopentanecarboxylic acid; D004791:Enzyme Inhibitors; D011392:Proline; D000612:4-Aminobutyrate Transaminase