8 research outputs found
Copper-Assisted Palladium(II)-Catalyzed Direct Arylation of Cyclic Enaminones with Arylboronic Acids
Described herein is a palladiumÂ(II)-catalyzed direct
arylation
of cyclic enaminones with arylboronic acids. The versatility of this
method is that both electron-rich and electron-poor boronic acids
can be coupled in high yields. A mixture of two CuÂ(II) additives was
crucial for efficient cross-coupling. The role of each CuÂ(II) reagent
appears to be distinct and complementary serving to assist catalyst
reoxidation and transmetalation through a putative arylcopper intermediate
Mapping the Protein Interaction Landscape for Fully Functionalized Small-Molecule Probes in Human Cells
Phenotypic screening provides a means
to discover small molecules
that perturb cell biological processes. Discerning the proteins and
biochemical pathways targeted by screening hits, however, remains
technically challenging. We recently described the use of small molecules
bearing photoreactive groups and latent affinity handles as fully
functionalized probes for integrated phenotypic screening and target
identification. The general utility of such probes, or, for that matter,
any small-molecule screening library, depends on the scope of their
protein interactions in cells, a parameter that remains largely unexplored.
Here, we describe the synthesis of an ∼60-member fully functionalized
probe library, prepared from Ugi-azide condensation reactions to impart
structural diversity and introduce diazirine and alkyne functionalities
for target capture and enrichment, respectively. In-depth mass spectrometry-based
analysis revealed a diverse array of probe targets in human cells,
including enzymes, channels, adaptor and scaffolding proteins, and
proteins of uncharacterized function. For many of these proteins,
ligands have not yet been described. Most of the probe–protein
interactions showed well-defined structure–activity relationships
across the probe library and were blocked by small-molecule competitors
in cells. These findings indicate that fully functionalized small
molecules canvas diverse segments of the human proteome and hold promise
as pharmacological probes of cell biology
Mapping the Protein Interaction Landscape for Fully Functionalized Small-Molecule Probes in Human Cells
Phenotypic screening provides a means
to discover small molecules
that perturb cell biological processes. Discerning the proteins and
biochemical pathways targeted by screening hits, however, remains
technically challenging. We recently described the use of small molecules
bearing photoreactive groups and latent affinity handles as fully
functionalized probes for integrated phenotypic screening and target
identification. The general utility of such probes, or, for that matter,
any small-molecule screening library, depends on the scope of their
protein interactions in cells, a parameter that remains largely unexplored.
Here, we describe the synthesis of an ∼60-member fully functionalized
probe library, prepared from Ugi-azide condensation reactions to impart
structural diversity and introduce diazirine and alkyne functionalities
for target capture and enrichment, respectively. In-depth mass spectrometry-based
analysis revealed a diverse array of probe targets in human cells,
including enzymes, channels, adaptor and scaffolding proteins, and
proteins of uncharacterized function. For many of these proteins,
ligands have not yet been described. Most of the probe–protein
interactions showed well-defined structure–activity relationships
across the probe library and were blocked by small-molecule competitors
in cells. These findings indicate that fully functionalized small
molecules canvas diverse segments of the human proteome and hold promise
as pharmacological probes of cell biology
Proteome-Wide Reactivity Profiling Identifies Diverse Carbamate Chemotypes Tuned for Serine Hydrolase Inhibition
Serine
hydrolases are one of the largest and most diverse enzyme
classes in Nature. Inhibitors of serine hydrolases are used to treat
many diseases, including obesity, diabetes, cognitive dementia, and
bacterial and viral infections. Nonetheless, the majority of the 200+
serine hydrolases in mammals still lack selective inhibitors for their
functional characterization. We and others have shown that activated
carbamates, through covalent reaction with the conserved serine nucleophile
of serine hydrolases, can serve as useful inhibitors for members of
this enzyme family. The extent to which carbamates, however, cross-react
with other protein classes remains mostly unexplored. Here, we address
this problem by investigating the proteome-wide reactivity of a diverse
set of activated carbamates <i>in vitro</i> and <i>in vivo</i>, using a combination of competitive and click chemistry
(CC)-activity-based protein profiling (ABPP). We identify multiple
classes of carbamates, including <i>O</i>-aryl, <i>O</i>-hexafluoroisopropyl (HFIP), and <i>O</i>-<i>N</i>-hydroxysuccinimidyl (NHS) carbamates that react selectively
with serine hydrolases across entire mouse tissue proteomes <i>in vivo</i>. We exploit the proteome-wide specificity of HFIP
carbamates to create <i>in situ</i> imaging probes for the
endocannabinoid hydrolases monoacylglycerol lipase (MAGL) and α-β
hydrolase-6 (ABHD6). These findings, taken together, designate the
carbamate as a privileged reactive group for serine hydrolases that
can accommodate diverse structural modifications to produce inhibitors
that display exceptional potency and selectivity across the mammalian
proteome
Remodeling Natural Products: Chemistry and Serine Hydrolase Activity of a Rocaglate-Derived β‑Lactone
Flavaglines
are a class of natural products with potent insecticidal
and anticancer activities. β-Lactones are a privileged structural
motif found in both therapeutic agents and chemical probes. Herein,
we report the synthesis, unexpected light-driven di-epimerization,
and activity-based protein profiling of a novel rocaglate-derived
β-lactone. In addition to <i>in vitro</i> inhibition
of the serine hydrolases ABHD10 and ACOT1/2, the most potent β-lactone
enantiomer was also found to inhibit these enzymes, as well as the
serine peptidases CTSA and SCPEP1, in PC3 cells
Remodeling Natural Products: Chemistry and Serine Hydrolase Activity of a Rocaglate-Derived β‑Lactone
Flavaglines
are a class of natural products with potent insecticidal
and anticancer activities. β-Lactones are a privileged structural
motif found in both therapeutic agents and chemical probes. Herein,
we report the synthesis, unexpected light-driven di-epimerization,
and activity-based protein profiling of a novel rocaglate-derived
β-lactone. In addition to <i>in vitro</i> inhibition
of the serine hydrolases ABHD10 and ACOT1/2, the most potent β-lactone
enantiomer was also found to inhibit these enzymes, as well as the
serine peptidases CTSA and SCPEP1, in PC3 cells
Remodeling Natural Products: Chemistry and Serine Hydrolase Activity of a Rocaglate-Derived β‑Lactone
Flavaglines
are a class of natural products with potent insecticidal
and anticancer activities. β-Lactones are a privileged structural
motif found in both therapeutic agents and chemical probes. Herein,
we report the synthesis, unexpected light-driven di-epimerization,
and activity-based protein profiling of a novel rocaglate-derived
β-lactone. In addition to <i>in vitro</i> inhibition
of the serine hydrolases ABHD10 and ACOT1/2, the most potent β-lactone
enantiomer was also found to inhibit these enzymes, as well as the
serine peptidases CTSA and SCPEP1, in PC3 cells
Evaluation of NHS Carbamates as a Potent and Selective Class of Endocannabinoid Hydrolase Inhibitors
Monoacylglycerol
lipase (MAGL) is a principal metabolic enzyme responsible for hydrolyzing
the endogenous cannabinoid (endocannabinoid) 2-arachidonoylglycerol
(2-AG). Selective inhibitors of MAGL offer valuable probes to further
understand the enzyme’s function in biological systems and
may lead to drugs for treating a variety of diseases, including psychiatric
disorders, neuroinflammation, and pain. <i>N</i>-Hydroxysuccinimidyl
(NHS) carbamates have recently been identified as a promising class
of serine hydrolase inhibitors that shows minimal cross-reactivity
with other proteins in the proteome. Here, we explore NHS carbamates
more broadly and demonstrate their potential as inhibitors of endocannabinoid
hydrolases and additional enzymes from the serine hydrolase class.
We extensively characterize an NHS carbamate <b>1a</b> (MJN110)
as a potent, selective, and in-vivo-active MAGL inhibitor. Finally,
we demonstrate that MJN110 alleviates mechanical allodynia in a rat
model of diabetic neuropathy, marking NHS carbamates as a promising
class of MAGL inhibitors