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The X-ray structure of the previously reported PPARδ modulator 1 bound to the ligand binding domain (LBD) revealed that the amide moiety in 1 exists in the thermodynamically disfavored cis-amide orientation. Isosteric replacement of the cis-amide with five-membered heterocycles led to the identification of imidazole 17 (MA-0204), a potent, selective PPARδ modulator with good pharmacokinetic properties. MA-0204 was tested in vivo in mice and in vitro in patient-derived muscle myoblasts (from Duchenne Muscular Dystrophy (DMD) patients); 17 altered the expression of PPARδ target genes and improved fatty acid oxidation, which supports the therapeutic hypothesis for the study of MA-0204 in DMD patients.

Compound 1 regulates significantly fewer genes than the PPARδ modulator, GW501516. Both compounds are efficacious in a thermal injury model of muscle regeneration. The restricted gene profile of 1 relative to GW501516 suggests that 1 may be pharmacoequivalent to GW501516 with fewer PPAR-related safety concerns.

p300 and its paralog CBP can acetylate histones and other proteins and have been implicated in a number of diseases characterized by aberrant gene activation, such as cancer. A novel, highly selective, orally bioavailable histone acetyltransferase (HAT) domain inhibitor has been identified through virtual ligand screening and subsequent optimization of a unique hydantoin screening hit. Conformational restraint in the form of a spirocyclization followed by substitution with a urea led to a significant improvement in potency. Replacement of the hydantoin moiety with an oxazolidinedione followed by fluoro substitution led to A-485, which exhibits potent cell activity, low clearance, and high oral bioavailability.

The dynamic and reversible acetylation of proteins, catalysed by histone acetyltransferases (HATs) and histone deacetylases (HDACs), is a major epigenetic regulatory mechanism of gene transcription and is associated with multiple diseases. Histone deacetylase inhibitors are currently approved to treat certain cancers, but progress on the development of drug-like histone actyltransferase inhibitors has lagged behind. The histone acetyltransferase paralogues p300 and CREB-binding protein (CBP) are key transcriptional co-activators that are essential for a multitude of cellular processes, and have also been implicated in human pathological conditions (including cancer). Current inhibitors of the p300 and CBP histone acetyltransferase domains, including natural products, bi-substrate analogues and the widely used small molecule C646, lack potency or selectivity. Here, we describe A-485, a potent, selective and drug-like catalytic inhibitor of p300 and CBP. We present a high resolution (1.95 Å) co-crystal structure of a small molecule bound to the catalytic active site of p300 and demonstrate that A-485 competes with acetyl coenzyme A (acetyl-CoA). A-485 selectively inhibited proliferation in lineage-specific tumour types, including several haematological malignancies and androgen receptor-positive prostate cancer. A-485 inhibited the androgen receptor transcriptional program in both androgen-sensitive and castration-resistant prostate cancer and inhibited tumour growth in a castration-resistant xenograft model. These results demonstrate the feasibility of using small molecule inhibitors to selectively target the catalytic activity of histone acetyltransferases, which may provide effective treatments for transcriptional activator-driven malignancies and diseases.

One of the most commonly used strategies to reduce hERG (human ether-a-go-go) activity in the drug candidates is introduction of a carboxylic acid group. During the optimization of PPARδ modulators, some of the compounds containing a carboxylic acid were found to inhibit the hERG channel in a patch clamp assay. By modifying the basicity of the imidazole core, potent and selective PPARδ modulators that do not inhibit hERG channel were identified. Some of the modulators have excellent pharmacokinetic profiles in mice.

[Image: see text] The X-ray structure of the previously reported PPARδ modulator 1 bound to the ligand binding domain (LBD) revealed that the amide moiety in 1 exists in the thermodynamically disfavored cis-amide orientation. Isosteric replacement of the cis-amide with five-membered heterocycles led to the identification of imidazole 17 (MA-0204), a potent, selective PPARδ modulator with good pharmacokinetic properties. MA-0204 was tested in vivo in mice and in vitro in patient-derived muscle myoblasts (from Duchenne Muscular Dystrophy (DMD) patients); 17 altered the expression of PPARδ target genes and improved fatty acid oxidation, which supports the therapeutic hypothesis for the study of MA-0204 in DMD patients.

The host restriction factor tetherin inhibits virion release from infected cells and poses a significant barrier to successful zoonotic transmission of primate lentiviruses to humans. While most simian immunodeficiency viruses (SIV), including the direct precursors of human immunodeficiency virus type 1 (HIV-1) and HIV-2, use their Nef protein to counteract tetherin in their natural hosts, they fail to antagonize the human tetherin ortholog. Pandemic HIV-1 group M and epidemic group O strains overcame this hurdle by adapting their Vpu and Nef proteins, respectively, whereas HIV-2 group A uses its envelope (Env) glycoprotein to counteract human tetherin. Whether or how the remaining eight groups of HIV-2 antagonize this antiviral factor has remained unclear. Here, we show that Nef proteins from diverse groups of HIV-2 do not or only modestly antagonize human tetherin, while their ability to downmodulate CD3 and CD4 is highly conserved. Experiments in transfected cell lines and infected primary cells revealed that not only Env proteins of epidemic HIV-2 group A but also those of a circulating recombinant form (CRF01_AB) and rare groups F and I decrease surface expression of human tetherin and significantly enhance progeny virus release. Intriguingly, we found that many SIVsmm Envs also counteract human as well as smm tetherin. Thus, Env-mediated tetherin antagonism in different groups of HIV-2 presumably stems from a preadaptation of their SIVsmm precursors to humans. In summary, we identified a phenotypic trait of SIVsmm that may have facilitated its successful zoonotic transmission to humans and the emergence of HIV-2. IMPORTANCE HIV-2 groups A to I resulted from nine independent cross-species transmission events of SIVsmm to humans and differ considerably in their prevalence and geographic spread. Thus, detailed characterization of these viruses offers a valuable means to elucidate immune evasion mechanisms and human-specific adaptations determining viral spread. In a systematic comparison of rare and epidemic HIV-2 groups and their simian SIVsmm counterparts, we found that the ability of Nef to downmodulate the primary viral entry receptor CD4 and the T cell receptor CD3 is conserved, while effects on CD28, CD74, and major histocompatibility complex class I surface expression vary considerably. Furthermore, we show that not only the Env proteins of HIV-2 groups A, AB, F, and I but also those of some SIVsmm isolates antagonize human tetherin. This finding helps to explain why SIVsmm has been able to cross the species barrier to humans on at least nine independent occasions.

Tetherin is an interferon-inducible restriction factor targeting a broad range of enveloped viruses. Its antiviral activity depends on an unusual topology comprising an N-terminal transmembrane domain (TMD) followed by an extracellular coiled-coil region and a C-terminal glycosylphosphatidylinositol (GPI) anchor. One of the two membrane anchors is inserted into assembling virions, while the other remains in the plasma membrane of the infected cell. Thus, tetherin entraps budding viruses by physically bridging viral and cellular membranes. Although tetherin restricts the release of a large variety of diverse human and animal viruses, only mammalian orthologs have been described to date. Here, we examined the evolutionary origin of this protein and demonstrate that tetherin orthologs are also found in fish, reptiles, and birds. Notably, alligator tetherin efficiently blocks the release of retroviral particles. Thus, tetherin emerged early during vertebrate evolution and acquired its antiviral activity before the mammal/reptile divergence. Although there is only limited sequence homology, all orthologs share the typical topology. Two unrelated proteins of the slime mold Dictyostelium discoideum also adopt a tetherin-like configuration with an N-terminal TMD and a C-terminal GPI anchor. However, these proteins showed no evidence for convergent evolution and failed to inhibit virion release. In summary, our findings demonstrate that tetherin emerged at least 450 million years ago and is more widespread than previously anticipated. The early evolution of antiviral activity together with the high topology conservation but low sequence homology suggests that restriction of virus release is the primary function of tetherin. IMPORTANCE The continuous arms race with viruses has driven the evolution of a variety of cell-intrinsic immunity factors that inhibit different steps of the viral replication cycle. One of these restriction factors, tetherin, inhibits the release of newly formed progeny virions from infected cells. Although tetherin targets a broad range of enveloped viruses, including retro-, filo-, herpes-, and arenaviruses, the evolutionary origin of this restriction factor and its antiviral activity remained obscure. Here, we examined diverse vertebrate genomes for genes encoding cellular proteins that share with tetherin the highly unusual combination of an N-terminal transmembrane domain and a C-terminal glycosylphosphatidylinositol anchor. We show that tetherin orthologs are found in fish, reptiles, and birds and demonstrate that alligator tetherin efficiently inhibits the release of retroviral particles. Our findings identify tetherin as an evolutionarily ancient restriction factor and provide new important insights into the continuous arms race between viruses and their hosts.

Mitophagy is one of the processes that cells use to maintain overall health. An E3 ligase, parkin, ubiquitinates mitochondrial proteins prior to their degradation by autophagasomes. USP30 is an enzyme that de-ubiquitinates mitochondrial proteins; therefore, inhibiting this enzyme could foster mitophagy. Herein, we disclose the structure-activity relationships (SAR) within a novel series of highly selective USP30 inhibitors. Two structurally similar compounds, MF-094 (a potent and selective USP30 inhibitor) and MF-095 (a significantly less potent USP30 inhibitor), serve as useful controls for biological evaluation. We show that MF-094 increases protein ubiquitination and accelerates mitophagy.

Optimization of benzamide PPARδ modulator 1 led to (E)-6-(2-((4-(furan-2-yl)-N-methylbenzamido)methyl)phenoxy)-4-methylhex-4-enoic acid (18), a potent selective PPARδ modulator with significantly improved exposure in multiple species following oral administration.

The NS3/4A serine protease of the hepatitis C virus (HCV) is one of the most attractive targets for specific antiviral agents. However, mutations conferring resistance may decrease the efficacy of these drugs. Although the level of resistance associated with specific mutations differs between different compounds, substitutions R155K and A156T reduce susceptibility to all protease inhibitors published so far. Interestingly, variants harboring the resistant mutation R155K were also detected as the predominant quasispecies in some treatment-naive patients. Of note, key positions for resistance overlap with the HLA-A*68-restricted epitope HAVGIFRAAV1175–1184. The aim of our study was to analyze the impact of protease inhibitor resistance mutations on the replication level and the antiviral CD8 T cell response against this HCV epitope. Our findings suggest that the R155K variant is associated with a relatively high replication level and with a substantial loss of cross-recognition by specific CD8 T cells targeting the epitope HAVGIFRAAV1175–1184, providing a possible explanation for its existence in the absence of drug selection pressure.

Structural modification of naturally occurring beta-lactams and beta-lactones is a highly effective strategy for generating drugs for treating bacterial infections, cancer, obesity, and hyperlipidemia. These drugs acylate catalytic amino acids (serine, threonine, or cysteine) in enzyme targets such as penicillin-binding proteins (PBPs), beta-lactamases, lipases, HMG-CoA reductase, fatty acid synthetase, and the 20S proteasome. Optimally performing drugs combine features of high target affinity, chemoselective reactivity, and high stability of the acylated target protein. This review provides a perspective on these two classes of acylating agents and summarizes recent advances in mechanism and structure-based design of acylating drugs.

The dynamic and reversible acetylation of proteins catalyzed by histone acetyltransferases (HATs) and histone deacetylases (HDACs) is a major epigenetic regulatory mechanism of gene transcription 1 associated with multiple diseases. While HDAC inhibitors are approved to treat certain cancers, progress on the development of drug-like HAT inhibitors has lagged 2. The HAT paralogs p300 and CBP (p300/CBP) are key transcriptional co-activators essential for a multitude of cellular processes and also implicated in human pathological conditions, including cancer 3. Current p300/CBP HAT domain inhibitors including natural products, 4 bi-substrate analogs (Lys-CoA) 5 and the widely utilized C646 6, 7 lack potency or selectivity. Here, we describe A-485, a potent, selective and drug-like p300/CBP catalytic inhibitor. We show the first high resolution (1.95Å) co-crystal structure of a small molecule bound to the catalytic active site of p300 and demonstrate that A-485 is acetyl-CoA competitive. A-485 selectively inhibited proliferation across lineage-specific tumor types, including several hematological malignancies and androgen receptor-positive prostate cancer. A-485 inhibited the androgen receptor transcriptional program in both androgen sensitive and castrate resistant prostate cancer and inhibited tumor growth in a castration resistant xenograft model. These results demonstrate the feasibility of selectively targeting the catalytic activity of histone acetyltransferases.

Summary Guanylate binding proteins (GBPs) are an interferon (IFN)-inducible subfamily of guanosine triphosphatases (GTPases) with well-established activity against intracellular bacteria and parasites. Here we show that GBP5 potently restricts HIV-1 and other retroviruses. GBP5 is expressed in the primary target cells of HIV-1, where it impairs viral infectivity by interfering with the processing and virion incorporation of the viral envelope glycoprotein (Env). GBP5 levels in macrophages determine and inversely correlate with infectious HIV-1 yield over several orders of magnitude, which may explain the high donor variability in macrophage susceptibility to HIV. Antiviral activity requires Golgi localization of GBP5, but not its GTPase activity. Start codon mutations in the accessory vpu gene from macrophage-tropic HIV-1 strains conferred partial resistance to GBP5 inhibition by increasing Env expression. Our results identify GBP5 as an antiviral effector of the IFN response and may explain the increased frequency of defective vpu genes in primary HIV-1 strains.

hen I left the island of Saipan after two years of Peace Corps service in the late 1960s, I promised myself that I would return as often as pos sible. That's not the same as living there, certainly not the same as having been born there. But it's a promise that I have kept and still keep. I was back in the early ipyos to work for the Congress of Micronesia's Future Political Status Commission, in the mid-ipyos to work for the Microne sian Constitutional Convention. Magazine assignments brought me back, as did the research for my 1991 book The Edge of Paradise: America in Micronesia. Most recently, I was invited back to give a speech in connec tion with the sixtieth anniversary of the World War II battle for Saipan. What follows is an edited version of "Saipan: From Then to Now," deliv ered to an audience of veterans and Saipan residents on 16 June 2004.

In this study, we explored the application of a yeast three-hybrid (Y3H)-based compound/protein display system to scanning the proteome for targets of kinase inhibitors. Various known cyclin-dependent kinase (CDK) inhibitors, including purine and indenopyrazole analogs, were displayed in the form of methotrexate-based hybrid ligands and deployed in cDNA library or yeast cell array-based screening formats. For all inhibitors, known cell cycle CDKs as well as novel candidate CDK-like and/or CDK-unrelated kinase targets could be identified, many of which were independently confirmed using secondary enzyme assays and affinity chromatography. The Y3H system described here may prove generally useful in the discovery of candidate drug targets.

We investigated cleavage surfaces perpendicular to the tenfold direction of as-grown decagonal Al–Ni–Co quasicrystals by scanning tunneling microscopy, Auger electron spectroscopy, and scanning electron microscopy. The cleavage surface is determined by a cluster–subcluster structure. The image contrast of the smallest features, 1–2 nm in diameter, is related to the columnar atom arrangements extending perpendicular to the cleavage plane, which are predicted by current models of the decagonal quasicrystal structure. No voltage dependence of the STM images is observed. The presence of surface states and an enhanced density of states are discussed. Heat-treatments of the cleaved Al–Ni–Co quasicrystal surfaces show nearly no changes in chemical composition and structure up to about 750 °C. This is correlated with a much lower concentration of vacancies in as-grown decagonal Al–Ni–Co quasicrystals as compared to that in as-grown icosahedral Al–Pd–Mn quasicrystals.

International audience; CXCL12-CXCR4 signaling controls multiple physiological processes and its dysregulation is associated with cancers and inflammatory diseases. To discover as-yet-unknown endogenous ligands of CXCR4, we screened a blood-derived peptide library for inhibitors of CXCR4-tropic HIV-1 strains. This approach identified a 16 amino acid fragment of serum albumin as an effective and highly specific CXCR4 antagonist. The endogenous peptide, termed EPI-X4, is evolutionarily conserved and generated from the highly abundant albumin precursor by pH-regulated proteases. EPI-X4 forms an unusual lasso-like structure and antagonizes CXCL12-induced tumor cell migration, mobilizes stem cells, and suppresses inflammatory responses in mice. Furthermore, the peptide is abundant in the urine of patients with inflammatory kidney diseases and may serve as a biomarker. Our results identify EPI-X4 as a key regulator of CXCR4 signaling and introduce proteolysis of an abundant precursor protein as an alternative concept for chemokine receptor regulation.

We analyze the shape of internal voids in as-grown and long term annealed icosahedral Al–Pd–Mn quasi-crystals and distinguish growth and equilibrium shapes. From the growth shape we extract that the growth speed anisotropy is pronounced and changes with the chemical composition of the bulk material, favoring primarily the formation of fivefold oriented surfaces, while only small surface areas of three and even smaller twofold facets are observed. In contrast the equilibrium shape of voids exhibits no effect of the chemical composition of the bulk material. We show that the surface free energy exhibits only a very small anisotropy. This leads to richly faceted voids with much more types of facets as compared to voids determined by the growth kinetics.

SummaryMost simian immunodeficiency viruses use their Nef protein to antagonize the host restriction factor tetherin. A deletion in human tetherin confers Nef resistance, representing a hurdle to successful zoonotic transmission. HIV-1 group M evolved to utilize the viral protein U (Vpu) to counteract tetherin. Although HIV-1 group O has spread epidemically in humans, it has not evolved a Vpu-based tetherin antagonism. Here we show that HIV-1 group O Nef targets a region adjacent to this deletion to inhibit transport of human tetherin to the cell surface, enhances virion release, and increases viral resistance to inhibition by interferon-α. The Nef protein of the inferred common ancestor of group O viruses is also active against human tetherin. Thus, Nef-mediated antagonism of human tetherin evolved prior to the spread of HIV-1 group O and likely facilitated secondary virus transmission. Our results may explain the epidemic spread of HIV-1 group O.

Topically applied microbicides potently inhibit HIV in vitro but have largely failed to exert protective effects in clinical trials. One possible reason for this discrepancy is that the preclinical testing of microbicides does not faithfully reflect the conditions of HIV sexual transmission. Here, we report that candidate microbicides that target HIV components show greatly reduced antiviral efficacy in the presence of semen, the main vector for HIV transmission. This diminished antiviral activity was dependent on the ability of amyloid fibrils in semen to enhance the infectivity of HIV. Thus, the anti-HIV efficacy of microbicides determined in the absence of semen greatly underestimated the drug concentrations needed to block semen-exposed virus. One notable exception was Maraviroc. This HIV entry inhibitor targets the host cell CCR5 coreceptor and was highly active against both untreated and semen-exposed HIV. These data help explain why microbicides have failed to protect against HIV in clinical trials and suggest that antiviral compounds targeting host factors hold promise for further development. These findings also suggest that the in vitro efficacy of candidate microbicides should be determined in the presence of semen to identify the best candidates for the prevention of HIV sexual transmission.

We investigated the changes in structure induced by heat treatment of cleaved fivefold icosahedral Al–Pd–Mn quasicrystal surfaces close to, and far away from, grown-in voids. Areas far away from grown-in voids exhibit a roughening connected above 620 K with a decrease of the Al concentration, and above 820 K a recovery of the surface composition. No change of the surface structure can be detected close to grown-in voids in the same temperature range. The results indicate that the surface structure is influenced by the presence of vacancies in the quasicrystals and that vacancies enhance the surface roughening during heat treatment.

A two-step evolution of the surface structure of in situ cleaved Czochralski-grown icosahedral Al–Pd–Mn single quasicrystals during heat treatment is found by scanning electron and scanning tunneling microscopies. At temperatures above 420°C the surface becomes rough in certain areas, while in other areas the cluster-based structure of the cleavage surface remains essentially unchanged. Above 550 to 600°C the rough surface areas exhibit larger faceted holes and the cluster-based surface structure reorders. Possible explanations of the two-step evolution are discussed.

Background The acquisition of effective Vpu-mediated anti-tetherin activity to promote virion release following transmission of SIVcpzPtt from central chimpanzees (Pan troglodytes troglodytes) to humans distinguishes pandemic HIV-1 group M strains from non-pandemic group N, O and P viruses and may have been a prerequisite for their global spread. Some functional motifs in the cytoplasmic region of HIV-1 M Vpus proposed to be important for anti-tetherin activity are more frequently found in the Vpu proteins of SIVcpzPtt than in those of SIVcpzPts infecting eastern chimpanzees (P. t. schweinfurthii), that have not been detected in humans, and SIVgor from gorillas, which is closely related to HIV-1 O and P. Thus, SIVcpzPtt strains may require fewer adaptive changes in Vpu than SIVcpzPts or SIVgor strains to counteract human tetherin. Results To examine whether SIVcpzPtt may only need changes in the transmembrane domain (TMD) of Vpu to acquire anti-tetherin activity, whereas SIVcpzPts and SIVgor may also require changes in the cytoplasmic region, we analyzed chimeras between the TMD of an HIV-1 M Vpu and the cytoplasmic domains of SIVcpzPtt (n = 2), SIVcpzPts (n = 2) and SIVgor (n = 2) Vpu proteins. Unexpectedly, all of these chimeras were capable of counteracting human tetherin to enhance virion release, irrespective of the presence or absence of the putative adaptor protein binding sites and the DSGxxS β-TrCP binding motif reported to be critical for effective anti-tetherin activity of M Vpus. It was also surprising that in three of the six chimeras the gain of anti-tetherin function was associated with a loss of the CD4 degradation activity since this function was conserved among all parental HIV-1, SIVcpz and SIVgor Vpu proteins. Conclusions Our results show that changes in the TMD of SIVcpzPtt, SIVcpzPts and SIVgor Vpus are sufficient to render them active against human tetherin. Thus, several previously described domains in the extracellular region of Vpu are not absolutely essential for tetherin antagonism but may be required for other Vpu functions.

HIV-1 groups M and N emerged within the last century following two independent cross-species transmissions of SIVcpz from chimpanzees to humans. In contrast to pandemic group M strains, HIV-1 group N viruses are exceedingly rare, with only about a dozen infections identified, all but one in individuals from Cameroon. Poor adaptation to the human host may be responsible for this limited spread of HIV-1 group N in the human population. Here, we analyzed the function of Vpu proteins from seven group N strains from Cameroon, the place where this zoonosis originally emerged. We found that these N-Vpus acquired four amino acid substitutions (E15A, V19A and IV25/26LL) in their transmembrane domain (TMD) that allow efficient interaction with human tetherin. However, despite these adaptive changes, most N-Vpus still antagonize human tetherin only poorly and fail to down-modulate CD4, the natural killer (NK) cell ligand NTB-A as well as the lipid-antigen presenting protein CD1d. These functional deficiencies were mapped to amino acid changes in the cytoplasmic domain that disrupt putative adaptor protein binding sites and an otherwise highly conserved ßTrCP-binding DSGxxS motif. As a consequence, N-Vpus exhibited aberrant intracellular localization and/or failed to recruit the ubiquitin-ligase complex to induce tetherin degradation. The only exception was the Vpu of a group N strain recently discovered in France, but originally acquired in Togo, which contained intact cytoplasmic motifs and counteracted tetherin as effectively as the Vpus of pandemic HIV-1 M strains. These results indicate that HIV-1 group N Vpu is under strong host-specific selection pressure and that the acquisition of effective tetherin antagonism may lead to the emergence of viral variants with increased transmission fitness., Author Summary Differences in their degree of adaptation to humans may explain why only one of four ape-derived SIV zoonoses spawned the AIDS pandemic. Specifically, only HIV-1 strains of the pandemic M group evolved a fully functional Vpu that efficiently antagonizes human tetherin and degrades CD4. In comparison, the rare group N viruses gained some anti-tetherin activity but lost the CD4 degradation function. Here, we show that the N-Vpu transmembrane domain has adapted to interact with human tetherin and identified the mutations that enable this interaction. However, we also show that most N-Vpus remain poor tetherin antagonists and fail to reduce the surface expression of CD4, the natural killer cell ligand NTB-A and the lipid-antigen presenting protein CD1d. This is due to mutations in their cytoplasmic region that are associated with aberrant protein localization and impaired interaction with the ubiquitin/proteasome pathway. A remarkable exception is the Vpu of the first HIV-1 N strain known to be transmitted outside of Cameroon, which contains a functional cytoplasmic domain and is a highly effective tetherin antagonist. These data indicate that group N viruses are still adapting to humans and that the acquisition of potent anti-tetherin activity may eventually lead to the emergence of viral variants that exhibit increased transmission fitness.

The enantiospecific Nicholas reaction, i.e. cobalt-promoted Friedel-Crafts reaction leading from chiral reactant to chiral product, was demonstrated for the first time.

Heteroatom substitution within the zileuton nucleus led to a congener series which was evaluated for potency and rate of glucuronidation, a major route for elimination of zileuton. Subtle changes in structure were found to significantly effect glucuronidation rate.

A series of novel aminoacyl adenylate mimics has been prepared and evaluated for their inhibitory activity against aminoacyl-tRNA synthetases. Several of these thiazole derivatives displayed potent and selective enzyme activity against both Gram-positive and Gram-negative bacteria.

A series of quinoline inhibitors of C. albicans prolyl tRNA synthetase was identified. The most potent analogue, 2-(4-bromo-phenyl)-6-chloro-8-methyl-4-quinolinecarboxylic acid, showed IC 50 =5 nM (Ca. ProRS) with high selectivity over the human enzyme.

In the past decade tremendous progress has been made toward a new class of therapeutics termed 'targeted covalent drugs', in which structure-based approaches are employed to create small molecules that inactivate their protein target through targeted covalent attachment to a specific cysteine. In the kinase field, this approach is demonstrating promise in overcoming the potency, selectivity, and efficacy challenges currently faced by reversible kinase inhibitors, with several advancing into late stage clinical testing. This design paradigm has been successfully applied to making drug candidates for epidermal growth factor receptor (EGFR), Her2, and Bruton's tyrosine kinase (Btk). Here we review recent pre-clinical and clinical advances with targeted covalent kinase inhibitors, and the potential for broader application of the approach.

Methods of measuring tissue area from images of longitudinal thin tooth sections have been used to assess sexual dimorphism in the permanent dentition. The aim of this study was to demonstrate the extent of sexual dimorphism within the coronal tissue proportions of permanent mandibular canines and premolars, using area measurements of the enamel and dentine-pulp core. The sample consisted of embedded "half-tooth" sections from 45 individuals, all of known age-at-death and sex, collected from the St. Thomas' Anglican Church historic (1821-1874) cemetery site in Belleville, ON, Canada. The relative dentine-pulp area of the third premolars and canines displayed high levels of sexual dimorphism, as well as statistically significant mean differences between the sexes. The male canines and premolars have significantly more dentine than their female counterparts, as well as relatively more dentine with respect to overall crown size. The female canines and premolars have significantly more enamel relative to overall crown area than those of the males. These results suggest that relative area measures of crown tissues are more predictable measures of sexual dimorphism than absolute measures, and tissue proportions may remain constant despite intrasex variation in overall tooth crown size.

Restriction factors are cellular proteins that inhibit viruses at different steps of their replication cycle and represent an important first line of defense against viral pathogens. This SnapShot provides an overview of cell-intrinsic antiviral factors, describes their properties, and illustrates the striking variety of antiviral mechanisms as well the sophisticated viral countermeasures. To view this SnapShot, open or download the PDF.

An alanine conjugate of a Candida albicans geranylgeranyl transferase I inhibitor was synthesized to facilitate its uptake into the fungal cell. The antifungal activity of CaGGTase-Ala conjugate is demonstrated. It is also shown that the CaGGTase-Ala conjugate affects prenylation of endogenous Rho1p, but has no effect on prenylation of endogenous Ras1p.

Diethyl [(2-tetrahydropyranyloxy)methyl]phosphonate intermediate: 33.63 g (0.2 mol) of diethyl hydroxymethylphosphonate product: Diethyl [(2-tetrahydropyranyloxy)methyl]phosphonate Keywords: acetal (and thioacetal) formation; addition, to CC; addition, to CO

We identified the presence and chemical nature of bulk vacancies in Al-Pd-Mn quasicrystals by measuring the structure and composition of two- and fivefold cleavage surfaces of different preannealed quasicrystals subjected to postcleavage heat treatments using scanning electron microscopy and Auger electron spectroscopy. A strong dependence of the surface structure from the preannealing is observed and explained by varying concentrations of bulk vacancies. The analysis of the data shows that as-grown Al-Pd-Mn quasicrystals contain Al, Pd, and Mn vacancies in supersaturated but near stoichiometric concentrations, while long-term preannealed samples contain a much lower vacancy concentration, with a tendency to have excess Al vacancies. We found that Al and Mn vacancies are more mobile at lower temperatures than Pd vacancies, and that the diffusion of Mn vacancies is directly coupled to the mobility of Al vacancies. The results demonstrate that the evolution of the surface structure is primarily affected by bulk vacancies migrating toward the surface during heat treatments and provide a new methodology to characterize the vacancies in intermetallic alloys.