Crystal structure of Staphylococcus aureus tyrosyl-tRNA synthetase in complex with a class of potent and specific inhibitors.

SB-219383 and its analogues are a class of potent and specific inhibitors of bacterial tyrosyl-tRNA synthetases. Crystal structures of these inhibitors have been solved in complex with the tyrosyl-tRNA synthetase from Staphylococcus aureus, the bacterium that is largely responsible for hospital-acquired infections. The full-length enzyme yielded crystals that diffracted to 2.8 A resolution, but a truncated version of the enzyme allowed the resolution to be extended to 2.2 A. These inhibitors not only occupy the known substrate binding sites in unique ways, but also reveal a butyl binding pocket. It was reported that the Bacillus stearothermophilus TyrRS T51P mutant has much increased catalytic activity. The S. aureus enzyme happens to have a proline at position 51. Therefore, our structures may contribute to the understanding of the catalytic mechanism and provide the structural basis for designing novel antimicrobial agents.

Inhibitors of bacterial tyrosyl tRNA synthetase: synthesis of carbocyclic analogues of the natural product SB-219383.

Carbocyclic analogues of the microbial metabolite SB-219383 have been synthesised and evaluated as inhibitors of bacterial tyrosyl tRNA synthetase. One compound showed highly potent and selective nanomolar inhibition.

Synthetic analogues of SB-219383. Novel C-glycosyl peptides as inhibitors of tyrosyl tRNA synthetase.

Novel inhibitors of bacterial tyrosyl tRNA synthetase have been synthesised in which the cyclic hydroxylamine moiety of SB-219383 is replaced by C-pyranosyl derivatives. Potent and selective inhibition of bacterial tyrosyl tRNA synthetase was obtained.

Potent synthetic inhibitors of tyrosyl tRNA synthetase derived from C-pyranosyl analogues of SB-219383.

Novel pyranosyl analogues of SB-219383 have been synthesised to elucidate the structure-activity relationships around the pyran ring. Analogues with highly potent stereoselective and bacterioselective inhibition of bacterial tyrosyl tRNA synthetase have been identified. A major reduction in the overall polarity of the molecule can be tolerated without loss of the nanomolar level of inhibition.

Inhibitors of bacterial tyrosyl tRNA synthetase: synthesis of four stereoisomeric analogues of the natural product SB-219383.

Synthetic analogues of the microbial metabolite SB-219383 have been synthesised with defined stereochemistry. Densely functionalised hydroxylamine containing amino acids were prepared by the addition of a glycine anion equivalent to sugar-derived cyclic nitrones. One of four stereoisomeric dipeptides incorporating these novel amino acids was found to be a potent and selective inhibitor of bacterial tyrosyl tRNA synthetase, suggesting analogous stereochemistry of the natural product.

Aminoalkyl adenylate and aminoacyl sulfamate intermediate analogues differing greatly in affinity for their cognate Staphylococcus aureus aminoacyl tRNA synthetases.

Aminoalkyl adenylates and aminoacyl sulfamates derived from arginine, histidine and threonine, have been prepared and tested as inhibitors of their cognate Staphylococcus aureus aminoacyl tRNA synthetases. The arginyl derivatives were both potent nanomolar inhibitors of the Class I arginyl tRNA synthetase whereas for the Class II histidyl and threonyl tRNA synthetases, the acyl sulfamates were potent inhibitors but the adenylates had very little affinity.

Synthesis and activity of analogues of SB-219383: novel potent inhibitors of bacterial tyrosyl tRNA synthetase.

SB-219383 is a naturally occurring antibiotic, which acts by inhibition of tyrosyl tRNA synthetase. Semi-synthetic derivatives of SB-219383 were prepared with the objective of elucidating the key features required for inhibition of tyrosyl tRNA synthetase in order to improve the antibacterial activity. Some ester and amide derivatives as well as monocyclic analogues exhibited sub-nanomolar inhibitory activity against tyrosyl tRNA synthetase.

Interaction of tyrosyl aryl dipeptides with S. aureus tyrosyl tRNA synthetase: inhibition and crystal structure of a complex.

Tyrosyl aryl dipeptide inhibitors of S. aureus tyrosyl tRNA synthetase have been identified with IC50 values down to 0.5 microM. A crystal structure of the enzyme complexed to one of the inhibitors shows occupancy of the tyrosyl binding pocket coupled with inhibitor interactions to key catalytic residues.

Inhibition of herpes proteases and antiviral activity of 2-substituted thieno[2,3-d]oxazinones.

Cinnamyl derivatives of thieno[2,3-d]oxazinones are mechanism-based inhibitors of the HSV-2, VZV and CMV herpes proteases which demonstrate nanomolar potency. Compounds 5 and 28 inhibit protease processing in HSV-2 infected cells with a selectivity index of at least 30.

Inhibition of human cytomegalovirus protease by enedione derivatives of thieno[2,3-d]oxazinones through a novel dual acylation/alkylation mechanism.

Enedione derivatives of thieno[2,3-d]oxazinones are nanomolar inhibitors of CMV protease which act through a novel dual acylation of the catalytic serine and alkylation of the protease cysteine 161 via a Michael addition to the enedione moiety of the inhibitor.