The mode of action of alpha sarcin and a novel assay of the puromycin reaction.
Ontology highlight
ABSTRACT:
SUBMITTER: Hobden AN
PROVIDER: S-EPMC1183860 | biostudies-other | 1978 Jan
REPOSITORIES: biostudies-other
Similar Datasets
Project description:We report structural, functional, and biochemical similarities between Argonautes, the effector proteins of RNA-induced silencing complexes (RISCs), and alpha-sarcin-like ribotoxins. At the structural level, regions of similarity in the amino acid sequence are located in protein loops both in the ribotoxins and in the Argonautes. In ribotoxins, these protein loops confer specificity for a highly conserved segment of ribosomal RNA, the Sarcin-Ricin-Loop (SRL) that undergoes cleavage by the ribotoxin ribonuclease. This leads to suppression of translation. In addition to the structural similarity with ribotoxins, the Argonaute proteins (Ago) show both functional and biochemical parallels. Like the ribotoxins, the Agos exhibit ribonuclease activity and like the ribotoxins, translational suppression mediated by miRISC-resident Ago is accompanied by intact polysomes. Furthermore, in both translationally suppressed systems, the puromycin reaction, reflecting correct translocation and peptidyl-transferase activities, is unharmed. These findings support a mechanism for Ago-miRISCs whereby regulated cleavage of ribosomal RNA leads to translational suppression.
| S-EPMC2895252 | biostudies-literature
Project description:The ribotoxin α-sarcin belongs to a family of ribonucleases that cleave the sarcin/ricin loop (SRL), a critical functional rRNA element within the large ribosomal subunit (60S), thereby abolishing translation. Whether α-sarcin targets the SRL only in mature 60S subunits remains unresolved. Here, we show that, in yeast, α-sarcin can cleave SRLs within late 60S pre-ribosomes containing mature 25S rRNA but not nucleolar/nuclear 60S pre-ribosomes containing 27S pre-rRNA in vivo. Conditional expression of α-sarcin is lethal, but does not impede early pre-rRNA processing, nuclear export and the cytoplasmic maturation of 60S pre-ribosomes. Thus, SRL-cleaved containing late 60S pre-ribosomes seem to escape cytoplasmic proofreading steps. Polysome analyses revealed that SRL-cleaved 60S ribosomal subunits form 80S initiation complexes, but fail to progress to the step of translation elongation. We suggest that the functional integrity of a α-sarcin cleaved SRL might be assessed only during translation.
| S-EPMC7293039 | biostudies-literature
Project description:Alpha-mangostin (α-MG) is a natural xanthone reported to exhibit rapid bactericidal activity against Gram-positive bacteria, and may therefore have potential clinical application in healthcare sectors. This study sought to identify the antibacterial mode of action of α-MG against Staphylococcus epidermidis RP62A through RNA-sequencing technology.
2018-04-19 | GSE113302 | GEO
Project description:1,4-Dioxane (1,4-DX) is an environmental contaminant found in drinking water throughout the United States (US). While it is a suspected liver carcinogen, there is no federal or state maximum contaminant level for 1,4-DX in drinking water. Very little is known about the mechanisms by which this chemical elicits liver carcinogenicity. In the present study, we performed chronic and short-term dosing studies in female BDF-1 mice to explore the toxic effects of 1,4-DX. Histopathology studies and a multi-omics approach (transcriptomics and metabolomics) were performed to investigate potential mechanisms of toxicity. Mice were exposed to various concentrations of 1,4-DX (0, 50, 500 and 5,000 mg/L) in their drinking water for one or four weeks. Immunohistochemical analysis of the liver revealed an increase in the number of H2AXγ-positive hepatocytes (a marker of DNA double strand breaks) in mice exposed to 5,000 mg/L 1,4-DX for one and four weeks. In addition, an expansion of precholangiocytes was observed after four weeks of 5,000 mg/L 1,4-DX exposure, as reflected by CK-7 immunostaining. An increase in these markers reflect both DNA damage and repair mechanisms. Liver transcriptomics profiling showed that exposure to 5,000 mg/L 1,4-DX for four weeks resulted in the differential expression of 65 genes compared to controls. Pathway analysis of the transcriptomic data revealed 1,4-DX-induced perturbations in multiple signaling pathways in the liver, including those involved in xenobiotic metabolism, nicotine degradation and glutathione-mediated detoxification. Changes to these pathways as a result of 1,4-DX exposure reflect would be predicted to impact the oxidative stress response, detoxification, and DNA damage. Liver, kidney, stool and urine metabolomics profiling revealed no effect of 5,000 mg/L 1,4-DX exposure for one or four weeks on metabolites. We speculate that this may be reflective of DNA damage being counterbalanced by the repair response, with the net result being a null overall effect on the systemic biochemistry of the exposed mice. Our results show a novel approach for the investigation of environmental chemicals that do not elicit cell death, but have activated the repair systems in response to 1,4-DX exposure
2021-01-25 | GSE158087 | GEO
Project description:Lipoproteins are characterized by a fatty acid moiety at their amino-terminus through which they are anchored into membranes. They fulfill a variety of essential functions in bacterial cells, such as cell wall maintenance, virulence, efflux of toxic elements including antibiotics, and uptake of nutrients. The posttranslational modification process of lipoproteins involves the sequential action of integral membrane enzymes and phospholipids as acyl donors. In recent years, the structures of the lipoprotein modification enzymes have been solved by X-ray crystallography leading to a greater insight into their function and the molecular mechanism of the reactions. The catalytic domains of the enzymes are exposed to the periplasm or external milieu and are readily accessible to small molecules. Since the lipoprotein modification pathway is essential in proteobacteria, it is a potential target for the development of novel antibiotics. In this review, we discuss recent literature on the structural characterization of the enzymes, and the in vitro activity assays compatible with high-throughput screening for inhibitors, with perspectives on the development of new antimicrobial agents.
| S-EPMC8048626 | biostudies-literature
Project description:Screening of various bisquaternary bisnaphthalimides against a variety of human pathogens revealed one compound, designated MT02, with strong inhibitory effects against gram-positive bacteria. The minimal inhibitory concentrations ranged from 0.31 µg/ml against community-acquired methicillin resistant Staphylococcus aureus (MRSA) strain USA300 to 20 µg/ml against Streptococcus pneumonia. DNA-microarray studies generated a transcriptional signature characterized by a strong increase of genes involved in DNA-metabolism, DNA-replication, SOS-response and transport of positively charged compounds. Radioactive whole cell labeling experiments indicated a strong impact of MT02 on bacterial DNA-replication. Furthermore, surface plasmon resonance and gel retardation experiments demonstrated direct binding of MT02 to DNA in a concentration dependent, reversible and sequence-unspecific manner. The data presented suggest that the bisquaternary bisnaphthalimide MT02 exerts anti-gram-positive activity by binding to DNA and thereby prohibiting appropriate DNA-replication. WT strain exposed to MT02 for 60 minutes in rich medium
2011-01-04 | E-GEOD-23077 | biostudies-arrayexpress
Project description:Screening of various bisquaternary bisnaphthalimides against a variety of human pathogens revealed one compound, designated MT02, with strong inhibitory effects against gram-positive bacteria. The minimal inhibitory concentrations ranged from 0.31 µg/ml against community-acquired methicillin resistant Staphylococcus aureus (MRSA) strain USA300 to 20 µg/ml against Streptococcus pneumonia. DNA-microarray studies generated a transcriptional signature characterized by a strong increase of genes involved in DNA-metabolism, DNA-replication, SOS-response and transport of positively charged compounds. Radioactive whole cell labeling experiments indicated a strong impact of MT02 on bacterial DNA-replication. Furthermore, surface plasmon resonance and gel retardation experiments demonstrated direct binding of MT02 to DNA in a concentration dependent, reversible and sequence-unspecific manner. The data presented suggest that the bisquaternary bisnaphthalimide MT02 exerts anti-gram-positive activity by binding to DNA and thereby prohibiting appropriate DNA-replication.
2011-01-04 | GSE23077 | GEO
Project description:Antibacterial mode of action of alpha-mangostin on Staphylococcus epidermidis
| PRJNA450895 | ENA
Project description:This data is part of a pre-publication release. For information on the proper use of pre-publication data shared by the Wellcome Trust Sanger Institute (including details of any publication moratoria), please see http://www.sanger.ac.uk/datasharing/The drug Praziquantel is the most commonly used drug for parasitic flatworms. It is currently being increasingly used in mass drug administration programmes, raising concerns over whether resistance will develop. Although widely used, its mode of action was until very recently uncertain. This study will investigate the praziquantel mode of action and resistance by sequencing the transcriptomes of Dugesia japonica and different stages and strains of S. mansoni.
2013-05-13 | E-ERAD-135 | biostudies-arrayexpress
Project description:Negative allosteric modulators (NAMs) of the human calcium-sensing receptor (CaSR) have previously failed to show efficacy in human osteoporosis clinical trials, but there is now significant interest in repurposing these drugs for hypocalcemic disorders and inflammatory lung diseases. However, little is known about how CaSR NAMs inhibit the response to endogenous activators. An improved understanding of CaSR negative allosteric modulation may afford the opportunity to develop therapeutically superior CaSR-targeting drugs. In an attempt to elucidate the mechanistic and structural basis of allosteric modulation mediated by the previously reported NAM, calhex231, we herein demonstrate that calhex231 actually potentiates or inhibits the activity of multiple CaSR agonists depending on whether it occupies one or both protomers in a CaSR dimer. These findings reveal a novel mechanism of mode-switching at a Class C G protein-coupled receptor that has implications for drug discovery and potential clinical utility.
| S-EPMC7089027 | biostudies-literature