Probing the steric requirements of the γ-aminobutyric acid aminotransferase active site with fluorinated analogues of vigabatrin

Juncosa, Jose I.; Groves, Andrew; Xia, Guoyao; Silverman, Richard B.

doi:10.1016/j.bmc.2012.12.009

Cited by 13 publications

(10 citation statements)

References 23 publications

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“…The residue was purified by flash chromatography (silica gel; hexane/AcOEt, 9 : 1 to AcOEt) to afford 30 mg (78 %) of 23 as colorless oil. The spectroscopic data fully matched with those reported in the literature [17] .

{[α]}_{normalD}^{20}

=−8.1 ( c 0.53, CHCl 3 ) [Lit [17] .…”

Section: Methodssupporting

confidence: 83%

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A Unified Strategy for the Synthesis of Natural Products Containing δ‐Hydroxy‐γ‐ Lactones through a Photoredox ATRA Reaction.

Fuentes-Pantoja

Cordero‐Vargas

2022

Eur J Org Chem

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A unified strategy for the synthesis of natural products containing δ‐hydroxy‐γ‐lactones as the main core is reported. This strategy is based on a photocatalyzed radical ionic sequence for the preparation of γ‐lactones. Depending on the necessities of the synthetic targets, the reaction conditions can be adjusted to access a diastereoisomeric mixture or a single diasteroisomer of the lactones. Also, δ‐lactones can be prepared by this method. The utility of this procedure was demonstrated by the total synthesis of five natural products.

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{[α]}_{normalD}^{20}

=−8.1 ( c 0.53, CHCl 3 ) [Lit [17] .…”

Section: Methodssupporting

confidence: 83%

“…The spectroscopic data fully matched with those reported in the literature. [17] a ½ � 20 D = À 8.1 (c 0.53, CHCl 3 ) [Lit. [17] a ½ � 25 D = À 11.0 (c 0.31, CHCl 3 ).…”

Section: (R)-5-((s)-1-hydroxyethyl)dihydrofuran-2(3h)-one (23)mentioning

confidence: 99%

A Unified Strategy for the Synthesis of Natural Products Containing δ‐Hydroxy‐γ‐ Lactones through a Photoredox ATRA Reaction.

Fuentes-Pantoja

Cordero‐Vargas

2022

Eur J Org Chem

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“…36 Computer simulations were carried out as previously described. 37 In essence, the ligands (including the cofactor) were docked into the active site of the prepared protein using Autodock 4.2, 38 with Lys329 being flexible. The best docked structures were then refined by molecular mechanics, using GROMACS 4.5.…”

Section: Methodsmentioning

confidence: 99%

Mechanism of Inactivation of γ-Aminobutyric Acid Aminotransferase by (1S,3S)-3-Amino-4-difluoromethylene-1-cyclopentanoic Acid (CPP-115)

Lee

Doud

et al. 2015

J. Am. Chem. Soc.

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γ-Aminobutyric acid aminotransferase (GABA-AT) is a pyridoxal 5′-phosphate (PLP)-dependent enzyme that degrades GABA, the principal inhibitory neurotransmitter in mammalian cells. When the concentration of GABA falls below a threshold level, convulsions can occur. Inhibition of GABA-AT raises GABA levels in the brain, which can terminate seizures as well as have potential therapeutic applications in treating other neurological disorders, including drug addiction. Among the analogues that we previously developed, (1S,3S)-3-amino-4-difluoromethylene-1-cyclopentanoic acid (CPP-115) showed 187 times greater potency than that of vigabatrin, a known inactivator of GABA-AT and approved drug (Sabril) for the treatment of infantile spasms and refractory adult epilepsy. Recently, CPP-115 was shown to have no adverse effects in a Phase I clinical trial. Here we report a novel inactivation mechanism for CPP-115, a mechanism-based inactivator that undergoes GABA-AT-catalyzed hydrolysis of the difluoromethylene group to a carboxylic acid with concomitant loss of two fluoride ions and coenzyme conversion to pyridoxamine 5′-phosphate (PMP). The partition ratio for CPP-115 with GABA-AT is about 2000, releasing cyclopentanone-2,4-dicarboxylate (22) and two other precursors of this compound (20 and 21). Time-dependent inactivation occurs by a conformational change induced by the formation of the aldimine of 4-aminocyclopentane-1,3-dicarboxylic acid and PMP (20), which disrupts an electrostatic interaction between Glu270 and Arg445 to form an electrostatic interaction between Arg445 and the newly formed carboxylate produced by hydrolysis of the difluoromethylene group in CPP-115, resulting in a noncovalent, tightly bound complex. This represents a novel mechanism for inactivation of GABA-AT and a new approach for the design of mechanism-based inactivators in general.

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“…To test for substrate activity of small molecules against OAT, we took a similar approach to the one we have previously developed for GABA-AT [12]. In essence, we wanted to detect the L-glutamate produced by OAT from α-ketoglutarate per turnover event (Scheme 2).…”

Section: Resultsmentioning

confidence: 99%

Two continuous coupled assays for ornithine-δ-aminotransferase

Juncosa

Lee

Silverman

2013

Analytical Biochemistry

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We have developed two new continuous, coupled assays for ornithine-δ-aminotransferase (OAT) that are more sensitive than previous methods, measure activity in real time, and can be carried out in multi-well plates for convenience and high throughput. The first assay is based on the reduction of Δ1-pyrroline-5-carboxylate (P5C), generated from ornithine by OAT, using human pyrroline 5-carboxylate reductase 1 (PYCR1), which results in the concomitant oxidation of NADH to NAD+. This procedure was found to be three times more sensitive than previous methods, and is suitable for the study of small molecules as inhibitors or inactivators of OAT or as a method to determine OAT activity in unknown samples. The second method involves the detection of L-glutamate, produced during the regeneration of the cofactor PLP of OAT by an unamplified modification of the commercially available Amplex® Red L-glutamate detection kit (Life Technologies). This assay is recommended for the determination of the substrate activity of small molecules against OAT; measuring the transformation of L-ornithine at high concentrations by this assay is complicated by the fact that it also acts as a substrate for the L-glutamate oxidase (GluOx) reporter enzyme.

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Probing the steric requirements of the γ-aminobutyric acid aminotransferase active site with fluorinated analogues of vigabatrin

Cited by 13 publications

References 23 publications

A Unified Strategy for the Synthesis of Natural Products Containing δ‐Hydroxy‐γ‐ Lactones through a Photoredox ATRA Reaction.

A Unified Strategy for the Synthesis of Natural Products Containing δ‐Hydroxy‐γ‐ Lactones through a Photoredox ATRA Reaction.

Mechanism of Inactivation of γ-Aminobutyric Acid Aminotransferase by (1S,3S)-3-Amino-4-difluoromethylene-1-cyclopentanoic Acid (CPP-115)

Two continuous coupled assays for ornithine-δ-aminotransferase

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