Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel cause cystic fibrosis. The ⌬F508 mutation produces defects in channel gating and cellular processing, whereas the G551D mutation produces primarily a gating defect. To identify correctors of gating, 50,000 diverse small molecules were screened at 2.5 M (with forskolin, 20 M) by an iodide uptake assay in epithelial cells coexpressing ⌬F508-CFTR and a fluorescent halide indicator (yellow fluorescent protein-H148Q/I152L) after ⌬F508-CFTR rescue by 24-h culture at 27°C. Secondary analysis and testing of Ͼ1000 structural analogs yielded two novel classes of correctors of defective ⌬F508-CFTR gating ("potentiators") with nanomolar potency that were active in human ⌬F508 and G551D cells. The most potent compound of the phenylglycine class, 2-[(2-1H-indol-3-yl-acetyl)-methylamino]-N-(4-isopropylphenyl)-2-phenylacetamide, reversibly activated ⌬F508-

Hypochlorous acid (HOCl) is produced naturally by neutrophils and other cells to kill conventional microbes in vivo. Synthetic preparations containing HOCl can also be effective as microbial disinfectants. Here we have tested whether HOCl can also inactivate prions and other self-propagating protein amyloid seeds. Prions are deadly pathogens that are notoriously difficult to inactivate, and standard microbial disinfection protocols are often inadequate. Recommended treatments for prion decontamination include strongly basic (pH ≥~12) sodium hypochlorite bleach, ≥1 N sodium hydroxide, and/or prolonged autoclaving. These treatments are damaging and/or unsuitable for many clinical, agricultural and environmental applications. We have tested the anti-prion activity of a weakly acidic aqueous formulation of HOCl (BrioHOCl) that poses no apparent hazard to either users or many surfaces. For example, BrioHOCl can be applied directly to skin and mucous membranes and has been aerosolized to treat entire rooms without apparent deleterious effects. Here, we demonstrate that immersion in BrioHOCl can inactivate not only a range of target microbes, including spores of Bacillus subtilis, but also prions in tissue suspensions and on stainless steel. Real-time quaking-induced conversion (RT-QuIC) assays showed that BrioHOCl treatments eliminated all detectable prion seeding activity of human Creutzfeldt-Jakob disease, bovine spongiform encephalopathy, cervine chronic wasting disease, sheep scrapie and hamster scrapie; these findings indicated reductions of ≥103- to 106-fold. Transgenic mouse bioassays showed that all detectable hamster-adapted scrapie infectivity in brain homogenates or on steel wires was eliminated, representing reductions of ≥~105.75-fold and >104-fold, respectively. Inactivation of RT-QuIC seeding activity correlated with free chlorine concentration and higher order aggregation or destruction of proteins generally, including prion protein. BrioHOCl treatments had similar effects on amyloids composed of human α-synuclein and a fragment of human tau. These results indicate that HOCl can block the self-propagating activity of prions and other amyloids.

The synthesis and Delta F508-CFTR corrector activity of a 148-member methylbithiazole-based library are reported. Synthetic routes were devised and optimized to generate methylbithiazole analogs in four steps. Corrector potency and efficacy were assayed using epithelial cells expressing human Delta F508-CFTR. These structure-activity data establish that the bithiazole substructure plays a critical function; eight novel methylbithiazole correctors were identified with low micromolar potencies.

The first step of lipid A biosynthesis is catalyzed by LpxA in Escherichia coli (EcLpxA), an acyltransferase selective for UDP-GlcNAc and R-3-hydroxymyristoyl-acyl carrier protein (ACP). Leptospira interrogans LpxA (LiLpxA) is extremely selective for R-3-hydroxylauroyl-ACP and an analogue of UDP-GlcNAc, designated UDP-GlcNAc3N, in which NH2 replaces the GlcNAc 3-OH group. EcLpxA does not discriminate between UDP-GlcNAc and UDP-GlcNAc3N; however, E. coli does not make UDP-GlcNAc3N. With LiLpxA R-3-hydroxylauroyl-methylphosphopantetheine efficiently substitutes for R-3-hydroxylauroyl-ACP. We now present crystal structures of free LiLpxA, and of its complexes with its product UDP-3-N-(R-3-hydroxylauroyl)-GlcNAc3N and with its substrate R-3-hydroxylauroyl-methylphosphopantetheine. The positions of the acyl chains of the R-3-hydroxylauroyl-methylphosphopantetheine and of the UDP-3-N-(R-3-hydroxylauroyl)-GlcNAc3N are almost identical, and are similar to that of the acyl chain in the EcLpxA/UDP-3-O-(R-3-hydroxymyristoyl)-GlcNAc complex. The selectivity of LiLpxA for UDP-GlcNAc3N may be explained by the orientation of the backbone carbonyl group of Q68, which differs by ∼82° from the corresponding Q73 carbonyl group in EcLpxA. This arrangement provides an extra hydrogen bond acceptor for the 3-NH2 group of UDP-GlcNAc3N in LiLpxA. The R-3-hydroxylauroyl-selectivity of LiLpxA is explained by the position of the K171 side chain, which limits the length of the acyl chain-binding groove. Our results support the role of LiLpxA H120 (which corresponds to EcLpxA H125) as the catalytic base and provide the first structural information about the orientation of the phosphopantetheine moiety during LpxA catalysis.