ABSTRACT
Herein, we demonstrate the design, synthesis, biophysical properties, and preliminary biological evaluation of 6-substituted indenoisoquinolines as a new class of G-quadruplex stabilizing small molecule ligands. We have synthesized 6-substituted indenoisoquinolines 1a-e in two steps from commercially available starting materials with excellent yields. The G-quadruplex stabilization potential of indenoisoquinolines 1a-e was evaluated by fluorescence resonance energy transfer-melting analysis, which showed that indenoisoquinolines show a high level of stabilization of various G-quadruplex DNA structures. Indenoisoquinolines demonstrated potent inhibition of cell growth in the GIST882 patient-derived gastrointestinal stromal tumor cell line, accompanied by inhibition of both c-Kit transcription and KIT oncoprotein levels.
ABSTRACT
Hydroxymethylphenoxy linkers that are commonly used in solid phase peptide synthesis are surprisingly susceptible to efficient cleavage by the protease chymotrypsin with a broad range of amino acid residues being tolerated at the scissile bond; this enzyme-cleavable linker system has been applied to peptide and glycopeptide synthesis.
Subject(s)
Chymotrypsin/metabolism , Combinatorial Chemistry Techniques/methods , Cross-Linking Reagents/chemistry , Glycopeptides/chemical synthesis , Peptides/chemical synthesis , Chymotrypsin/chemistry , Glycopeptides/chemistry , Hydrolysis , Molecular Structure , Peptides/chemistryABSTRACT
A range of glycopeptides containing protease cleavage sites were synthesized on solid support using Fmoc-based solid phase glycopeptide synthesis. The immobilized peptides were studied as substrates for the proteases chymotrypsin and thermolysin. For chymotrypsin, N-glycosylation of an Asn residue at the P(2) site appears to reduce hydrolysis whereas glycosylation of the P(1) site does not appear to affect peptide hydrolysis by thermolysin.
ABSTRACT
[reaction: see text] Chemical glycopeptide synthesis requires access to gram quantities of glycosylated amino acid building blocks. Hence, the efficiency of synthesis of such building blocks is of great importance. Here, we report a fast and highly efficient synthetic route to Fmoc-protected asparaginyl glycosides from unprotected sugars in three steps with high yields. The glycosylated amino acids were successfully incorporated into target glycopeptides 7 and 8 by standard Fmoc solid-phase peptide synthesis.
