Thio-Linked UDP–Peptide Conjugates as O‑GlcNAc Transferase Inhibitors

• Published in: Bioconjugate chemistry 2018-06, Vol.29 (6), p.1834-1840
• Main Authors: Rafie, Karim, Gorelik, Andrii, Trapannone, Riccardo, Borodkin, Vladimir S, van Aalten, Daan M. F
• Format: Article
• Language: English
• Subjects: Communication; Conjugates; Conjugation; Crystal structure; Drug Design; Enzyme Inhibitors - chemistry; Enzyme Inhibitors - pharmacology; Enzymes; Fluorescence; Glycosyltransferase; HeLa Cells; Humans; Inhibitors; Lysates; Mimicry; Molecular Docking Simulation; N-Acetylglucosaminyltransferases - antagonists & inhibitors; N-Acetylglucosaminyltransferases - metabolism; Peptides; Peptides - chemistry; Peptides - pharmacology; Polarimetry; Post-translation; Proteins; Proteomes; Prototypes; Serine; Substrates; Sulfhydryl Compounds - chemistry; Sulfhydryl Compounds - pharmacology; Uridine Diphosphate - analogs & derivatives; Uridine Diphosphate - pharmacology
• ISSN: 1043-1802; 1520-4812
• DOI: 10.1021/acs.bioconjchem.8b00194

O-GlcNAc transferase (OGT) is an essential glycosyltransferase that installs the O-GlcNAc post-translational modification on the nucleocytoplasmic proteome. We report the development of S-linked UDP–peptide conjugates as potent bisubstrate OGT inhibitors. These compounds were assembled in a modular fashion by photoinitiated thiol–ene conjugation of allyl-UDP and optimal acceptor peptides in which the acceptor serine was replaced with cysteine. The conjugate VTPVC­(S-propyl-UDP)­TA (K i = 1.3 μM) inhibits the OGT activity in HeLa cell lysates. Linear fusions of this conjugate with cell penetrating peptides were explored as prototypes of cell-penetrant OGT inhibitors. A crystal structure of human OGT with the inhibitor revealed mimicry of the interactions seen in the pseudo-Michaelis complex. Furthermore, a fluorophore-tagged derivative of the inhibitor works as a high affinity probe in a fluorescence polarimetry hOGT assay.