Cyclic Boronates Inhibit All Classes of β-Lactamase

β-Lactamase-mediated resistance is a growing threat to the continued use of β-lactam antibiotics. The use of the β-lactam-based serine-β-lactamase (SBL) inhibitors clavulanic acid, sulbactam, tazobactam, and, more recently, the non-β-lactam inhibitor avibactam has extended the utility of β-lactams against bacterial infections demonstrating resistance via these enzymes. These molecules are, however, ineffective against the metallo-β-lactamases (MBLs), which catalyse their hydrolysis. To date, there are no clinically available metallo-β-lactamase inhibitors. Co-production of MBLs and SBLs in resistant infections is, thus, of major clinical concern. The development of ‘dual-action' inhibitors, targeting both SBLs and MBLs, is of interest, but these are considered difficult to achieve due to the structural and mechanistic differences between the two enzyme classes. We recently reported evidence that cyclic boronates can inhibit both serine- and metallo-β-lactmases. Here we report that cyclic boronates are able to inhibit all four classes of β-lactamase, including the class A extended spectrum β-lactamase, CTX-M-15, the class C enzyme, AmpC from Pseudomonas aeruginosa, and class D OXA enzymes with carbapenem-hydrolysing capabilities. We demonstrate that cyclic boronates can potentiate the use of β-lactams against Gram-negative clinical isolates expressing a variety of β-lactamases. Comparison of a crystal structure of a CTX-M-15:cyclic boronate complex with structures of cyclic boronates complexed with other β-lactamases reveals remarkable conservation of the small molecule binding mode, supporting our proposal that these molecules work by mimicking the common tetrahedral anionic intermediate present in both serine- and metallo-β-lactamase catalysis

Biocatalytic production of bicyclic β-lactams with three contiguous chiral centres using engineered crotonases

YesThere is a need to develop asymmetric routes to functionalised β-lactams, which remain the most important group of antibacterials. Here we describe biocatalytic and protein engineering studies concerning carbapenem biosynthesis enzymes, aiming to enable stereoselective production of functionalised carbapenams with three contiguous chiral centres. Structurallyguided substitutions of wildtype carboxymethylproline synthases enable tuning of their C-N and C-C bond forming capacity to produce 5-carboxymethylproline derivatives substituted at C-4 and C-6, from amino acid aldehyde and malonyl-CoA derivatives. Use of tandem enzyme incubations comprising an engineered carboxymethylproline synthase and an alkylmalonylCoA forming enzyme (i.e. malonyl-CoA synthetase or crotonyl-CoA carboxylase reductase) can improve stereocontrol and expand the product range. Some of the prepared 4,6-disubstituted-5-carboxymethylproline derivatives are converted to bicyclic β-lactams by carbapenam synthetase catalysis. The results illustrate the utility of tandem enzyme systems involving engineered crotonases for asymmetric bicyclic β-lactam synthesis

New Delhi metallo-β-lactamase-1 catalyses avibactam and aztreonam hydrolysis.

Metallo-β-lactamases (MBLs) threaten the clinical utility of β-lactam antibiotics by hydrolysing penicillins, cephalosporins, and carbapenem

New Delhi metallo-β-lactamase-1 catalyses avibactam and aztreonam hydrolysis.

Metallo-β-lactamases (MBLs) threaten the clinical utility of β-lactam antibiotics by hydrolysing penicillins, cephalosporins, and carbapenem

Inhibition of a viral prolyl hydroxylase

The hydroxylation of prolyl-residues in eukaryotes is important in collagen biosynthesis and in hypoxic signalling. The hypoxia inducible factor (HIF) prolyl hydroxylases (PHDs) are drug targets for the treatment of anaemia, while the procollagen prolyl hydroxylases and other 2-oxoglutarate dependent oxygenases are potential therapeutic targets for treatment of cancer, fibrotic disease, and infection. We describe assay development and inhibition studies for a procollagen prolyl hydroxylase from Paramecium bursaria chlorella virus 1 (vCPH). The results reveal HIF PHD inhibitors in clinical trials also inhibit vCPH. Implications for the targeting of the human PHDs and microbial prolyl hydroxylases are discussed