Ubiquitin chain variability directs substrates of the Tul1 ubiquitin ligase complex to different degradation pathways.

Cellular protein quality control consists of multiple, networked systems that survey and maintain a healthy eukaryotic proteome. In Saccharomyces cerevisiae, the transmembrane ubiquitin ligase 1 (Tul1) complex is an integral membrane protein quality control system that functions within the Golgi-endosomal system. Golgi-localized Tul1 complexes target proteins for degradation by either the cytosolic proteasome or the vacuole.

Identification of ERAD-dependent degrons for the endoplasmic reticulum lumen.

Degrons are minimal protein features that are sufficient to target proteins for degradation. In most cases, degrons allow recognition by components of the cytosolic ubiquitin proteasome system. Currently, all of the identified degrons only function within the cytosol.

Identification of ERAD-dependent degrons for the endoplasmic reticulum lumen.

Degrons are minimal protein features that are sufficient to target proteins for degradation. In most cases, degrons allow recognition by components of the cytosolic ubiquitin proteasome system. Currently, all of the identified degrons only function within the cytosol.

Novel chemical entities inhibiting Mycobacterium tuberculosis growth identified by phenotypic high-throughput screening.

We performed a high-throughput phenotypic whole cell screen of Mycobacterium tuberculosis against a diverse chemical library of approximately 100,000 compounds from the AbbVie corporate collection and identified 24 chemotypes with anti-tubercular activity. We selected two series for further exploration and conducted structure-activity relationship studies with new analogs for the 4-phenyl piperidines (4PP) and phenylcyclobutane carboxamides (PCB). Strains with mutations in MmpL3 demonstrated resistance to both compound series.

Novel Trifluoromethyl Pyrimidinone Compounds With Activity Against .

The identification and development of new anti-tubercular agents are a priority research area. We identified the trifluoromethyl pyrimidinone series of compounds in a whole-cell screen against . Fifteen primary hits had minimum inhibitory concentrations (MICs) with good potency IC is the concentration at which growth is inhibited by 90% (IC < 5 μM).

Multiple Mutations in Mycobacterium tuberculosis MmpL3 Increase Resistance to MmpL3 Inhibitors.

The protein MmpL3 performs an essential role in cell wall synthesis, since it effects the transport of trehalose monomycolates across the inner membrane. Numerous structurally diverse pharmacophores have been identified as inhibitors of MmpL3 largely based on the identification of resistant isolates with mutations in MmpL3. For some compounds, it is possible there are different primary or secondary targets.

RnhP is a plasmid-borne RNase HI that contributes to genome maintenance in the ancestral strain Bacillus subtilis NCIB 3610.

RNA-DNA hybrids form throughout the chromosome during normal growth and under stress conditions. When left unresolved, RNA-DNA hybrids can slow replication fork progression, cause DNA breaks, and increase mutagenesis. To remove hybrids, all organisms use ribonuclease H (RNase H) to specifically degrade the RNA portion.

Efficacy and Improved Resistance Potential of a Cofactor-Independent InhA Inhibitor of Mycobacterium tuberculosis in the C3HeB/FeJ Mouse Model.

AN12855 is a direct, cofactor-independent inhibitor of InhA in In the C3HeB/FeJ mouse model with caseous necrotic lung lesions, AN12855 proved efficacious with a significantly lower resistance frequency than isoniazid. AN12855 drug levels were better retained in necrotic lesions and caseum where the majority of hard to treat, extracellular bacilli reside. Owing to these combined attributes, AN12855 represents a promising alternative to the frontline antituberculosis agent isoniazid.

A class of hydrazones are active against non-replicating Mycobacterium tuberculosis.

There is an urgent need for the development of shorter, simpler and more tolerable drugs to treat antibiotic tolerant populations of Mycobacterium tuberculosis. We previously identified a series of hydrazones active against M. tuberculosis.

In Vitro Evaluation of Novel Nitazoxanide Derivatives against .

Nitazoxanide has antiparasitic and antibiotic activities including activity against . We prepared and evaluated a set of its analogues to determine the structure-activity relationship, and identified several amide- and urea-based analogues with low micromolar activity against in vitro. Pharmacokinetics in the rat suggested a path forward to obtain bioavailable compounds.

Mechanisms of resistance against NITD-916, a direct inhibitor of Mycobacterium tuberculosis InhA.

Isoniazid inhibits Mycobacterium tuberculosis InhA and is a key component of drug regimens that treat tuberculosis. However, the high rate of resistance against isoniazid is a contributing factor to the emergence of multi-drug resistance strains of M. tuberculosis.

Isolation and Characterization of Oxazolidinone-Resistant Mycobacterium tuberculosis.

Oxazolidinones are promising candidates for the treatment of infections. We isolated linezolid-resistant strains from H37Rv (Euro-American) and HN878 (East-Asian) strains; resistance frequencies were similar in the two strains. Mutations were identified in ribosomal protein L3 (RplC) and the 23S rRNA ().

Mutations in MmpL3 alter membrane potential, hydrophobicity and antibiotic susceptibility in Mycobacterium smegmatis.

MmpL3 is a promising target for novel anti-tubercular agents, with numerous compound series identified as MmpL3 inhibitors. Despite this, there is an incomplete understanding of MmpL3 function. Here we show that Mycobacterium smegmatis MmpL3 mutant strains had an altered cell wall hydrophobicity, disrupted membrane potential and growth defects in liquid media.