Browsing by keyword "Hydrocarbons, Fluorinated"
Now showing items 1-3 of 3
-
A fluoroacetamidine-based inactivator of protein arginine deiminase 4: design, synthesis, and in vitro and in vivo evaluationProtein arginine deiminase 4 (PAD4) is a calcium-dependent transcriptional corepressor that has been implicated in the onset and progression of rheumatoid arthritis. Herein we describe the synthesis and in vitro evaluation of a fluoroacetamidine-containing compound, N-alpha-benzoyl-N5-(2-fluoro-1-iminoethyl)-l-ornithine amide, 1, hereafter referred to as F-amidine, that is the most potent PAD4 inhibitor ever described. Additional studies described herein indicate that F-amidine can also inhibit PAD4 activity in vivo. The bioavailability of this compound suggests that F-amidine will be a powerful chemical probe of PAD4 function that can be used to dissect the roles of this enzyme in both rheumatoid arthritis and transcriptional control. The fact that inhibition is of an irreversible nature suggests that, with appropriate functionalization, F-amidine analogues will be robust activity-based protein-profiling and proteomic capture reagents.
-
Inhibitors and inactivators of protein arginine deiminase 4: functional and structural characterizationProtein arginine deiminase 4 (PAD4) is a transcriptional coregulator that catalyzes the calcium-dependent conversion of specific arginine residues in proteins to citrulline. Recently, we reported the synthesis and characterization of F-amidine, a potent and bioavailable irreversible inactivator of PAD4. Herein, we report our efforts to identify the steric and leaving group requirements for F-amidine-induced PAD4 inactivation, the structure of the PAD4-F-amidine x calcium complex, and in vivo studies with N-alpha-benzoyl-N5-(2-chloro-1-iminoethyl)-L-ornithine amide (Cl-amidine), a PAD4 inactivator with enhanced potency. The PAD4 inactivators described herein will be useful pharmacological probes in characterizing the incompletely defined physiological role(s) of this enzyme. In addition, they represent potential lead compounds for the treatment of rheumatoid arthritis because a growing body of evidence supports a role for PAD4 in the onset and progression of this chronic autoimmune disorder.
-
Synthesis and screening of a haloacetamidine containing library to identify PAD4 selective inhibitors.Protein arginine deiminase activity (PAD) is increased in cancer, rheumatoid arthritis, and ulcerative colitis. Although the link between abnormal PAD activity and disease is clear, the relative contribution of the individual PADs to human disease is not known; there are 5 PAD isozymes in humans. Building on our previous development of F- and Cl-amidine as potent pan-PAD irreversible inhibitors, we describe herein a library approach that was used to identify PAD-selective inhibitors. Specifically, we describe the identification of Thr-Asp-F-amidine (TDFA) as a highly potent PAD4 inactivator that displays > /=15-fold selectivity for PAD4 versus PAD1 and > /=50-fold versus PADs 2 and 3. This compound is active in cells and can be used to inhibit PAD4 activity in cellulo. The structure of the PAD4.TDFA complex has also been solved, and the structure and mutagenesis data indicate that the enhanced potency is due to interactions between the side chains of Q346, R374, and R639. Finally, we converted TDFA into a PAD4-selective ABPP and demonstrated that this compound, biotin-TDFA, can be used to selectively isolate purified PAD4 in vitro. In total, TDFA and biotin-TDFA represent PAD4-selective chemical probes that can be used to study the physiological roles of this enzyme.