ABSTRACT
3-Methoxybenzamide (1) is a weak inhibitor of the essential bacterial cell division protein FtsZ. Alkyl derivatives of 1 are potent antistaphylococcal compounds with suboptimal drug-like properties. Exploration of the structure-activity relationships of analogues of these inhibitors led to the identification of potent antistaphylococcal compounds with improved pharmaceutical properties.
Subject(s)
Anti-Bacterial Agents/chemical synthesis , Bacterial Proteins/antagonists & inhibitors , Cytoskeletal Proteins/antagonists & inhibitors , Pyridines/chemical synthesis , Staphylococcus aureus/drug effects , Thiazoles/chemical synthesis , Animals , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Biological Availability , Blood Proteins/metabolism , Caco-2 Cells , Cell Division/drug effects , Cell Membrane Permeability , Hepatocytes/metabolism , Humans , Mice , Microbial Sensitivity Tests , Models, Molecular , Protein Binding , Pyridines/chemistry , Pyridines/pharmacology , Staphylococcal Infections/drug therapy , Staphylococcus aureus/cytology , Structure-Activity Relationship , Thiazoles/chemistry , Thiazoles/pharmacologyABSTRACT
FtsZ is an essential bacterial guanosine triphosphatase and homolog of mammalian beta-tubulin that polymerizes and assembles into a ring to initiate cell division. We have created a class of small synthetic antibacterials, exemplified by PC190723, which inhibits FtsZ and prevents cell division. PC190723 has potent and selective in vitro bactericidal activity against staphylococci, including methicillin- and multi-drug-resistant Staphylococcus aureus. The putative inhibitor-binding site of PC190723 was mapped to a region of FtsZ that is analogous to the Taxol-binding site of tubulin. PC190723 was efficacious in an in vivo model of infection, curing mice infected with a lethal dose of S. aureus. The data validate FtsZ as a target for antibacterial intervention and identify PC190723 as suitable for optimization into a new anti-staphylococcal therapy.
Subject(s)
Anti-Bacterial Agents/pharmacology , Bacillus subtilis/drug effects , Bacterial Proteins/antagonists & inhibitors , Cytoskeletal Proteins/antagonists & inhibitors , Pyridines/pharmacology , Staphylococcal Infections/drug therapy , Staphylococcus aureus/drug effects , Thiazoles/pharmacology , Amino Acid Sequence , Animals , Anti-Bacterial Agents/therapeutic use , Bacillus subtilis/chemistry , Bacillus subtilis/genetics , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Binding Sites , Cell Division/drug effects , Crystallography, X-Ray , Cytoskeletal Proteins/chemistry , Cytoskeletal Proteins/genetics , Cytoskeletal Proteins/metabolism , Drug Resistance, Bacterial/genetics , Drug Resistance, Multiple, Bacterial , Ligands , Methicillin Resistance , Mice , Microbial Sensitivity Tests , Models, Molecular , Molecular Sequence Data , Mutation , Protein Conformation , Pyridines/chemistry , Pyridines/metabolism , Pyridines/therapeutic use , Staphylococcus aureus/chemistry , Thiazoles/chemistry , Thiazoles/metabolism , Thiazoles/therapeutic use , Tubulin/chemistry , Tubulin/metabolismABSTRACT
The hydrolysis of the plant cell wall by microbial glycoside hydrolases and esterases is the primary mechanism by which stored organic carbon is utilized in the biosphere, and thus these enzymes are of considerable biological and industrial importance. Plant cell wall-degrading enzymes in general display a modular architecture comprising catalytic and non-catalytic modules. The X4 modules in glycoside hydrolases represent a large family of non-catalytic modules whose function is unknown. Here we show that the X4 modules from a Cellvibrio japonicus mannanase (Man5C) and arabinofuranosidase (Abf62A) bind to polysaccharides, and thus these proteins comprise a new family of carbohydrate-binding modules (CBMs), designated CBM35. The Man5C-CBM35 binds to galactomannan, insoluble amorphous mannan, glucomannan, and manno-oligosaccharides but does not interact with crystalline mannan, cellulose, cello-oligosaccharides, or other polysaccharides derived from the plant cell wall. Man5C-CBM35 also potentiates mannanase activity against insoluble amorphous mannan. Abf62A-CBM35 interacts with unsubstituted oat-spelt xylan but not substituted forms of the hemicellulose or xylo-oligosaccharides, and requires calcium for binding. This is in sharp contrast to other xylan-binding CBMs, which interact in a calcium-independent manner with both xylo-oligosaccharides and decorated xylans.
