ABSTRACT
Here we describe an NMR and X-ray crystallography-based characterisation of the mechanism by which a new class of macrocyclic peptidomimetic aldehyde inhibits α-chymotrypsin. In particular, a (13)C-labelled analogue of the inhibitor was prepared and used in NMR experiments to confirm formation of a hemiacetal intermediate on binding with α-chymotrypsin. Analysis of an X-ray crystallographic structure in complex with α-chymotrypsin reveals that the backbone adopts a stable ß-strand conformation as per its design. Binding is further stabilised by interaction with the oxyanion hole near the S1 subsite and multiple hydrogen bonds.
Subject(s)
Aldehydes/pharmacology , Chymotrypsin/antagonists & inhibitors , Enzyme Inhibitors/pharmacology , Macrocyclic Compounds/pharmacology , Peptidomimetics/pharmacology , Aldehydes/chemical synthesis , Aldehydes/chemistry , Crystallography, X-Ray , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Macrocyclic Compounds/chemical synthesis , Macrocyclic Compounds/chemistry , Magnetic Resonance Spectroscopy , Models, Molecular , Molecular Structure , Peptidomimetics/chemical synthesis , Peptidomimetics/chemistryABSTRACT
The absorbance and fluorescence spectra of carboxylated spiropyrans containing methyl-1-aza-12-crown-4, methyl-1-aza-15-crown-5, methyl-1-aza-18-crown-6 moieties are compared. Characteristic changes in spectra after addition of the alkali metal salts of Li(+), Na(+), K(+) and Cs(+) were observed. Chromism induced by the binding of the metal cations was observed as an increase in absorbance and fluorescence. Of these metal cations, the Li(+) ion produced the largest change in all three spiropyran systems. Reversible photoswitching of the spiropyran-metal complexes was observed on irradiation with alternating 352 nm UV and white light. This results in reversible fluorescence based sensing of lithium ions with potential for use in a biological sensor device.
ABSTRACT
The interaction of IGF-II with the insulin receptor (IR) and type 1 insulin-like growth factor receptor (IGF-1R) has recently been identified as potential therapeutic target for the treatment of cancer. Understanding the interactions of IGF-II with these receptors is required for the development of potential anticancer therapeutics. This work describes an efficient convergent synthesis of native IGF-II and two non-native IGF-II analogues with coumarin fluorescent probes incorporated at residues 19 and 28. These fluorescent analogues bind with nanomolar affinities to the IGF-1R and are suitable for use in fluorescence resonance energy transfer (FRET) studies. From these studies the F19Cou IGF-II and F28Cou IGF-II proteins were identified as good probes for investigating the binding interactions of IGF-II with the IGF-1R and its other high affinity binding partners.
Subject(s)
Fluorescence Resonance Energy Transfer , Fluorescence , Insulin-Like Growth Factor II/chemistry , Receptor, IGF Type 1/chemistry , Binding Sites , Insulin-Like Growth Factor II/analogs & derivatives , Molecular StructureABSTRACT
Acetyl-CoA carboxylase (ACC) catalyses the first committed step in fatty acid biosynthesis: a metabolic pathway required for several important biological processes including the synthesis and maintenance of cellular membranes. ACC employs a covalently attached biotin moiety to bind a carboxyl anion and then transfer it to acetyl-CoA, yielding malonyl-CoA. These activities occur at two different subsites: the biotin carboxylase (BC) and carboxyltransferase (CT). Structural biology, together with small molecule inhibitor studies, has provided new insights into the molecular mechanisms that govern ACC catalysis, specifically the BC and CT subunits. Here, we review these recent findings and highlight key differences between the bacterial and eukaryotic isozymes with a view to establish those features that provide an opportunity for selective inhibition. Especially important are examples of highly selective small molecule inhibitors capable of differentiating between ACCs from different phyla. The implications for early stage antibiotic discovery projects, stemming from these studies, are discussed.
Subject(s)
Acetyl-CoA Carboxylase , Anti-Bacterial Agents/pharmacology , Bacteria/drug effects , Bacteria/enzymology , Enzyme Inhibitors/pharmacology , Acetyl-CoA Carboxylase/antagonists & inhibitors , Acetyl-CoA Carboxylase/chemistry , Acetyl-CoA Carboxylase/genetics , Acetyl-CoA Carboxylase/metabolism , Anti-Bacterial Agents/chemistry , Enzyme Inhibitors/chemistry , Fatty Acids/biosynthesis , Humans , Models, MolecularABSTRACT
The central nervous system glutamate receptors are an important target for drug discovery. Herein we report initial investigations into the synthesis and glutamate receptor activity of 1,2,3-triazolyl amino acids. Two compounds were found to be selective AMPA receptor ligands, which warrant further investigation.
Subject(s)
Amino Acids/chemistry , Receptors, AMPA/antagonists & inhibitors , Triazoles/chemistry , Amino Acids/chemical synthesis , Amino Acids/pharmacology , Binding Sites , Catalysis , Computer Simulation , Copper/chemistry , Ligands , Receptors, AMPA/metabolism , Ruthenium/chemistryABSTRACT
The design, synthesis, photoisomerism and biological testing of two peptide-based photoswitchable inhibitors of alpha-chymotrypsin are presented. The use of a dipeptide recognition sequence gave a 'slow-tight binding' inhibitor, while the introduction of a carbamate linker to the azobenzene gave a modest enhancement in photoswitching of enzyme activity for the photostationary state enriched in the (Z)-isomer over the (E)-isomer.
Subject(s)
Carbamates/chemistry , Carbamates/pharmacology , Chymotrypsin/antagonists & inhibitors , Phenylalanine/chemistry , Phenylalanine/pharmacology , Photochemistry/methods , Serine Proteinase Inhibitors/chemistry , Serine Proteinase Inhibitors/pharmacology , Binding Sites , Biochemistry/methods , Carbamates/metabolism , Chymotrypsin/metabolism , Drug Evaluation, Preclinical , Peptides/chemistry , Peptides/pharmacology , Phenylalanine/analogs & derivatives , Phenylalanine/metabolism , Serine Proteinase Inhibitors/metabolism , Structure-Activity Relationship , Ultraviolet RaysABSTRACT
The design and synthesis of a new peptide isostere which contains a trans alkene core is described. The key step involves a Wadsworth-Emmons reaction between chiral aldehyde (2S)-9a and chiral phosphonate 7 under base-sensitive conditions to give a chiral enone (2R)-24a which was reduced to afford the desired trans alkene isosteres (2R,5R)-6a and (2R,5S)-6b (Scheme 6). A potential application of this isostere in the synthesis of HIV protease inhibitors is also discussed.
Subject(s)
Anti-HIV Agents/chemical synthesis , HIV Protease Inhibitors/chemical synthesis , Nelfinavir/chemical synthesis , Saquinavir/chemical synthesis , Anti-HIV Agents/chemistry , HIV Protease Inhibitors/chemistry , Indicators and Reagents , Magnetic Resonance Spectroscopy , Molecular Conformation , Spectrometry, Mass, Electrospray IonizationABSTRACT
N-Acyl and N-sulfonylhydroxymetyhylpyrroles have been synthesised and shown to inhibit alpha-chymotrypsin. A hydrophobic group in the N-substituent has been shown to be required for activity.
Subject(s)
Chymotrypsin/antagonists & inhibitors , Pyrroles/pharmacology , Serine Proteinase Inhibitors/pharmacology , Animals , Cattle , Kinetics , Pyrroles/chemical synthesis , Serine Proteinase Inhibitors/chemical synthesis , Structure-Activity RelationshipABSTRACT
An unusual tetrazolodiazepin-6-one was prepared and shown, by X-ray crystallography, to adopt an essentially planar conformation about the tetrazole ring with geometry that closely approximates a cis-amide bond.
ABSTRACT
A number of tricyclic thiolactams, bicyclic lactams, and bicyclic thiolactams have been prepared and evaluated in vitro as inhibitors of types 1 and 2 steroid 5alpha-reductase. The tricycles with an 8-chloro substituent in the C-ring are nM (IC50) inhibitors of type 1 steroid 5alpha-reductase (SR). In all the cases studied, lactams are more potent than the corresponding thiolactams. Activity against type 2 SR is greatly enhanced by a styryl (or azo) substituent on the aryl ring of the tri- and bicycles and also a related tricyclic aryl acid.
Subject(s)
5-alpha Reductase Inhibitors , Enzyme Inhibitors/pharmacology , Lactams/pharmacology , Humans , Structure-Activity RelationshipABSTRACT
A kinetic analysis of the inhibition of malt alpha-amylase by compounds based on ascorbic acid has shown the mode of inhibition to be competitive for the parent compound, but more complex for its derivatives. We have further simplified the ascorbic acid ene-diol pharmacophore by demonstrating that dihydroxyfumaric acid is also a good inhibitor of malt alpha-amylase.
Subject(s)
Ascorbic Acid/analogs & derivatives , Ascorbic Acid/chemical synthesis , Enzyme Inhibitors/chemical synthesis , alpha-Amylases/antagonists & inhibitors , Ascorbic Acid/chemistry , Ascorbic Acid/pharmacology , Edible Grain/enzymology , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Kinetics , Molecular Structure , Structure-Activity RelationshipABSTRACT
The inhibition of human leukocyte elastase (HLE), and other serine proteases, by succinimide and saccharin-based compounds is reviewed. The succinimide compounds are unique in that the inactivating species is generated within the enzyme active site via a molecular rearrangement. The related saccharin derivatives also inactivate serine proteases by an enzyme-activated mechanism. Those factors effecting the potency, selectivity and stability of these important classes of inhibitor are discussed.
Subject(s)
Leukocyte Elastase/antagonists & inhibitors , Saccharin/pharmacology , Serine Proteinase Inhibitors/pharmacology , Succinimides/pharmacology , Binding Sites , Humans , Structure-Activity RelationshipABSTRACT
The four stereoisomers of 3-(N-acetylleucylamino)-3-benzyl-1-[(methylsulfonyl)oxy]succinimid e have been prepared and shown to inhibit alpha-chymotrypsin and human neutrophil elastase. The structural and stereochemical features that affect the potency and selectivity of inhibition are discussed.
Subject(s)
Leucine/chemistry , Phenylalanine/chemistry , Serine Proteinase Inhibitors/chemical synthesis , Succinimides/chemical synthesis , Chymotrypsin/antagonists & inhibitors , Dipeptides/chemistry , Humans , Leukocyte Elastase/antagonists & inhibitors , Serine Proteinase Inhibitors/chemistry , Serine Proteinase Inhibitors/pharmacology , Stereoisomerism , Succinimides/chemistry , Succinimides/pharmacologyABSTRACT
We report a general method for the synthesis of mycalazol 11 and some related 5-acyl-2-hydroxymethylpyrroles using a Stille coupling of 5-(tri-n-butylstannyl)pyrrole-2-carboxaldehyde with an acid chloride as the key step. The newly prepared 5-acyl-2-hydroxymethylpyrroles 5-7, together with the 5-carboxamido-2-hydroxymethylpyrrole 10, have been assayed for in vitro cytotoxicity against the P388 murine leukemia cell line.
Subject(s)
Antineoplastic Agents/chemical synthesis , Leukemia P388/pathology , Pyrroles/chemistry , Pyrroles/chemical synthesis , Pyrroles/pharmacology , Animals , Antineoplastic Agents/pharmacology , Drug Screening Assays, Antitumor , Magnetic Resonance Spectroscopy , MiceABSTRACT
A series of ascorbic acid and isoascorbic acid derivatives has been evaluated as inhibitors of malt, bacterial, fungal, pancreatic and salivary alpha-amylases using a simple and quick assay procedure. The results demonstrate that the enediol moiety of ascorbic acid is essential for alpha-amylase inhibition. Acylation of the primary and secondary alcohols, and the absolute configuration of the secondary alcohol, do not affect the potency of inhibition.
Subject(s)
Antithrombins/chemistry , Ascorbic Acid/chemistry , Enzyme Inhibitors/pharmacology , alpha-Amylases/antagonists & inhibitors , Antithrombin Proteins , Antithrombins/pharmacology , Enzyme Inhibitors/chemistry , KineticsABSTRACT
Hypochlorous acid generated by neutrophil myeloperoxidase has been shown to convert cholesterol into three different chlorohydrin isomers which previously had not been fully characterized. We have reacted hypochlorous acid with cholesterol/1,2-dipalmitoyl phosphatidylcholine liposomes to give these three major products and established that they are 6 beta-chloro-5 alpha-cholestane-3 beta,5-diol (chlorohydrin 1), 5 alpha-chloro-6 beta-cholestane-3,6-diol (chlorohydrin 2) and 6 alpha-chloro-5 beta-cholestane-3 beta,5-diol (chlorohydrin 3). These products were separated by thin-layer chromatography and fully characterized by 1H, 13C, attached proton test, doublequantum correlation spectroscopy, total correlation spectroscopy, heteronuclear multiple bond correlation and heteronuclear multiple quantum coherence nuclear magnetic resonance spectroscopy.