ABSTRACT
Designed ligands that inhibit hypoxia-inducible gene expression could offer new tools for genomic research and, potentially, drug discovery efforts for the treatment of neovascularization in cancers. We report a stabilized alpha-helix designed to target the binding interface between the C-terminal transactivation domain (C-TAD) of hypoxia-inducible factor 1alpha (HIF-1alpha) and cysteine-histidine rich region (CH1) of transcriptional coactivator CBP/p300. The synthetic helix disrupts the structure and function of this complex, resulting in a rapid downregulation of two hypoxia-inducible genes (VEGF and GLUT1) in cell culture.
Subject(s)
Disulfides/pharmacology , Hypoxia-Inducible Factor 1/antagonists & inhibitors , Indole Alkaloids/pharmacology , Trans-Activators/antagonists & inhibitors , Cell Survival/drug effects , Cells, Cultured , HeLa Cells , Humans , Hydrogen Bonding , Hypoxia-Inducible Factor 1/chemistry , Hypoxia-Inducible Factor 1/metabolism , Protein Structure, Secondary , Trans-Activators/chemistry , Trans-Activators/metabolismABSTRACT
This manuscript discusses microwave-assisted solid-phase synthesis of hydrogen-bond surrogate based alpha-helices and analogues by ring-closing metathesis (RCM). Microwave-mediated RCM allows access to a greater variety of amino acid residues in the macrocycles in shorter reaction times and higher yields compared to conventional heating. Surprisingly, we discovered that the Grubbs II catalyst is highly active under the influence of microwaves but catalytically dead under oil-bath conditions for the metathesis of these peptide bisolefins. [reaction: see text]
Subject(s)
Amino Acids/chemistry , Alkenes/chemistry , Catalysis , Chromatography, High Pressure Liquid , Cyclization , Hot Temperature , Hydrogen Bonding , Microwaves , Peptides/chemical synthesis , Protein Conformation , Protein Structure, Secondary , SolventsABSTRACT
[reaction: see text] This report describes the solid-phase synthesis of hydrogen-bond surrogate-derived artificial alpha-helices by a ring-closing metathesis reaction. From a series of metathesis catalysts evaluated for the synthesis of these helices, the Hoveyda-Grubbs catalyst was found to afford high yields of the macrocycle irrespective of the peptide sequence.
Subject(s)
Peptides/chemistry , Peptides/chemical synthesis , Catalysis , Cyclization , Hydrogen Bonding , Molecular Structure , Protein Structure, SecondaryABSTRACT
Herein we describe a strategy for the preparation of artificial alpha-helices involving replacement of one of the main-chain hydrogen bonds with a covalent linkage. To mimic the C=O...H-N hydrogen bond as closely as possible, we envisioned a covalent bond of the type C=X-Y-N, where X and Y are two carbon atoms connected through an olefin metathesis reaction. Our results demonstrate that the replacement of a hydrogen bond between the i and i + 4 residues at the N-terminus of a short peptide with a carbon-carbon bond results in a highly stable constrained alpha-helix at physiological conditions as indicated by CD and NMR spectroscopies. The advantage of this strategy is that it allows access to short alpha-helices with strict preservation of molecular recognition surfaces required for biomolecular interactions.
