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De novo drug discovery is still a challenge in the search for potent and selective modulators of therapeutically relevant target proteins. Here, we disclose the unexpected discovery of a peptidic ligand 1 by X-ray crystallography, which was auto-tailored by the therapeutic target MMP-13 through partial self-degradation and subsequent structure-based optimization to a highly potent and selective β-sheet peptidomimetic inhibitor derived from the endogenous tissue inhibitors of metalloproteinases (TIMPs). The incorporation of non-proteinogenic amino acids in combination with a cyclization strategy proved to be key for the de novo design of TIMP peptidomimetics. The optimized cyclic peptide 4 (ZHAWOC7726) is membrane permeable with an IC50 of 21 nm for MMP-13 and an attractive selectivity profile with respect to a polypharmacology approach including the anticancer targets MMP-2 (IC50 : 170 nm) and MMP-9 (IC50 : 140 nm).

Leucinostatin A is one of the most potent antiprotozoal compounds ever described, but little was known on structure-activity relationships (SAR). We used Trypanosoma brucei as a protozoal model organism to test synthetically modified derivatives, resulting in simplified but equally active compounds 2 (ZHAWOC6025) and 4 (ZHAWOC6027), which were subsequently modified in all regions of the molecule to gain an in-depth SAR understanding. The antiprotozoal SAR matched SAR in phospholipid liposomes, where membrane integrity, leaking, and dynamics were studied. The mode of action is discussed based on a structure-activity analysis of derivatives in efficacy, ultrastructural studies in T. brucei, and artificial membrane models, mimicking membrane stability and membrane potential. The main site of antiprotozoal action of natural and synthetic leucinostatins lies in the destabilization of the inner mitochondrial membrane, as demonstrated by ultrastructural analysis, electron microscopy and mitochondrial staining. Long-time sublethal exposure of T. brucei (200 passages) and siRNA screening of 12'000 mutants showed no signs of resistance development to the synthetic derivatives.

Zugehöriger Artikel: https://digitalcollection.zhaw.ch/handle/11475/21751

Back cover: https://doi.org/10.1002/anie.202104896, Leucinostatin A is one of the most potent antiprotozoal compounds ever described, but little was known on structure-activity relationships (SAR). We used Trypanosoma brucei as a protozoal model organism to test synthetically modified derivatives, resulting in simplified but equally active compounds 2 (ZHAWOC6025) and 4 (ZHAWOC6027), which were subsequently modified in all regions of the molecule to gain an in-depth SAR understanding. The antiprotozoal SAR matched SAR in phospholipid liposomes, where membrane integrity, leaking, and dynamics were studied. The mode of action is discussed based on a structure-activity analysis of derivatives in efficacy, ultrastructural studies in T. brucei, and artificial membrane models, mimicking membrane stability and membrane potential. The main site of antiprotozoal action of natural and synthetic leucinostatins lies in the destabilization of the inner mitochondrial membrane, as demonstrated by ultrastructural analysis, electron microscopy and mitochondrial staining. Long-time sublethal exposure of T. brucei (200 passages) and siRNA screening of 12'000 mutants showed no signs of resistance development to the synthetic derivatives.

Zugehöriger Artikel: https://digitalcollection.zhaw.ch/handle/11475/21751

Finding strategies against the development of antibiotic resistance is a major global challenge for the life sciences community and for public health. The past decades have seen a dramatic worldwide increase in human-pathogenic bacteria that are resistant to one or multiple antibiotics. More and more infections caused by resistant microorganisms fail to respond to conventional treatment, and in some cases, even lastresort antibiotics have lost their power. In addition, industry pipelines for the development of novel antibiotics have run dry over the past decades. A recent world health day by the World Health Organization titled “Combat drug resistance: no action today means no cure tomorrow” triggered an increase in research activity, and several promising strategies have been developed to restore treatment options against infections by resistant bacterial pathogens.

A sensitive indicator of nuclease activity is the fluorescence behavior of phosphodiesters 1 and 2. Although 1 and 2 do not fluoresce due to intramolecular quenching, the strongly fluorescent naphthyl phosphates and naphthols are liberated upon hydrolysis. This gives rise to an extremely strong increase in fluorescence intensity. Combined application of 1 and 2 allows detection of phosphatase in addition to phosphodiesterase activity. f = fluorophore, q = quencher.

Seek, and ye shall find: After years of focusing research on synthetic antibiotics out of fear that all the useful natural ones had already been found, a novel antibacterial compound has been discovered through conventional microbial extract screening. The broad-spectrum nucleoside-analogue inhibitor pseudouridimycin is selective for bacterial RNA polymerase and elicits very low resistance rates.

Finding strategies against the development of antibiotic resistance is a major global challenge for the life sciences community and for public health. The past decades have seen a dramatic worldwide increase in human-pathogenic bacteria that are resistant to one or multiple antibiotics. More and more infections caused by resistant microorganisms fail to respond to conventional treatment, and in some cases, even lastresort antibiotics have lost their power. In addition, industry pipelines for the development of novel antibiotics have run dry over the past decades. A recent world health day by the World Health Organization titled “Combat drug resistance: no action today means no cure tomorrow” triggered an increase in research activity, and several promising strategies have been developed to restore treatment options against infections by resistant bacterial pathogens.

A sensitive indicator of nuclease activity is the fluorescence behavior of phosphodiesters 1 and 2. Although 1 and 2 do not fluoresce due to intramolecular quenching, the strongly fluorescent naphthyl phosphates and naphthols are liberated upon hydrolysis. This gives rise to an extremely strong increase in fluorescence intensity. Combined application of 1 and 2 allows detection of phosphatase in addition to phosphodiesterase activity. f = fluorophore, q = quencher.

Seek, and ye shall find: After years of focusing research on synthetic antibiotics out of fear that all the useful natural ones had already been found, a novel antibacterial compound has been discovered through conventional microbial extract screening. The broad-spectrum nucleoside-analogue inhibitor pseudouridimycin is selective for bacterial RNA polymerase and elicits very low resistance rates.