Ribosomal oxygenases are structurally conserved from prokaryotes to humans

2-Oxoglutarate (2OG)-dependent oxygenases have important roles in the regulation of gene expression via demethylation of N-methylated chromatin components1,2 and in the hydroxylation of transcription factors3 and splicing factor proteins4. Recently, 2OG-dependent oxygenases that catalyse hydroxylation of transfer RNA5,6,7 and ribosomal proteins8 have been shown to be important in translation relating to cellular growth, TH17-cell differentiation and translational accuracy9,10,11,12. The finding that ribosomal oxygenases (ROXs) occur in organisms ranging from prokaryotes to humans8 raises questions as to their structural and evolutionary relationships. In Escherichia coli, YcfD catalyses arginine hydroxylation in the ribosomal protein L16; in humans, MYC-induced nuclear antigen (MINA53; also known as MINA) and nucleolar protein 66 (NO66) catalyse histidine hydroxylation in the ribosomal proteins RPL27A and RPL8, respectively. The functional assignments of ROXs open therapeutic possibilities via either ROX inhibition or targeting of differentially modified ribosomes. Despite differences in the residue and protein selectivities of prokaryotic and eukaryotic ROXs, comparison of the crystal structures of E. coli YcfD and Rhodothermus marinus YcfD with those of human MINA53 and NO66 reveals highly conserved folds and novel dimerization modes defining a new structural subfamily of 2OG-dependent oxygenases. ROX structures with and without their substrates support their functional assignments as hydroxylases but not demethylases, and reveal how the subfamily has evolved to catalyse the hydroxylation of different residue side chains of ribosomal proteins. Comparison of ROX crystal structures with those of other JmjC-domain-containing hydroxylases, including the hypoxia-inducible factor asparaginyl hydroxylase FIH and histone Nε-methyl lysine demethylases, identifies branch points in 2OG-dependent oxygenase evolution and distinguishes between JmjC-containing hydroxylases and demethylases catalysing modifications of translational and transcriptional machinery. The structures reveal that new protein hydroxylation activities can evolve by changing the coordination position from which the iron-bound substrate-oxidizing species reacts. This coordination flexibility has probably contributed to the evolution of the wide range of reactions catalysed by oxygenases

Central auditory processing disorder (CAPD) tests in a school-age hearing screening programme – analysis of 76,429 children

Introduction and objective Hearing disorders among school-age children are a current concern. Continuing studies have been performed in Poland since 2008, and on 2 December 2011 the EU Council adopted Conclusions on the Early Detection and Treatment of Communication Disorders in Children, Including the Use of e-Health Tools and innovative Solutions. The discussion now focuses not only on the efficacy of hearing screening programmes in schoolchildren, but what should be its general aim and what tests it should include? This paper makes the case that it is important to include central auditory processing disorder (CAPD) tests. One such test is the dichotic digits test (DDT). The aim of the presented study was to evaluate the usefulness of the DDT in detecting central hearing disorders in school-age children. Material and Methods During hearing screening programmes conducted in Poland in 2008–2010, exactly 235,664 children (7–12-years-old) were screened in 9,325 schools. Of this number, 7,642 were examined using the DDT test for CAPD. Screening programmes were conducted using the Sense Examination Platform. Results With the cut-off criterion set at the 5th percentile, results for the DDT applied in a divided attention mode were 11.4% positive for 7-year-olds and 11.3% for 12-year-olds. In the focused attention mode, the comparable result for 12-year-olds was 9.7%. There was a clear right ear advantage. In children with positive DDT results, a higher incidence of other disorders, such as dyslexia, was observed. Conclusions A test for CAPD should be included in the hearing screening of school-age children. The results of this study form the basis for developing Polish standards in this are

SALMON: Solvent Accessibility, Ligand binding, and Mapping of ligand Orientation by NMR Spectroscopy

Quinone oxidoreductase 2 (NQO2) binds the prodrug tretazicar (also known as CB1954, 5-(aziridin-1-yl)-2,4-dinitrobenzamide), which exhibits a profound antitumor effect in human cancers when administered together with caricotamide. X-ray structure determination allowed for two possible orientations of the ligand. Here we describe a new NMR method, SALMON (solvent accessibility, ligand binding, and mapping of ligand orientation by NMR spectroscopy), based on waterLOGSY to determine the orientation of a ligand bound to a protein by mapping its solvent accessibility, which was used to unambiguously determine the orientation of CB1954 in NQO2

The inhibition of human farnesyl pyrophosphate synthase by nitrogen-containing bisphosphonates. Elucidating the role of active site threonine 201 and tyrosine 204 residues using enzyme mutants

AbstractFarnesyl pyrophosphate synthase (FPPS) is the major molecular target of nitrogen-containing bisphosphonates (N-BPs), used clinically as bone resorption inhibitors. We investigated the role of threonine 201 (Thr201) and tyrosine 204 (Tyr204) residues in substrate binding, catalysis and inhibition by N-BPs, employing kinetic and crystallographic studies of mutated FPPS proteins.Mutants of Thr201 illustrated the importance of the methyl group in aiding the formation of the Isopentenyl pyrophosphate (IPP) binding site, while Tyr204 mutations revealed the unknown role of this residue in both catalysis and IPP binding. The interaction between Thr201 and the side chain nitrogen of N-BP was shown to be important for tight binding inhibition by zoledronate (ZOL) and risedronate (RIS), although RIS was also still capable of interacting with the main-chain carbonyl of Lys200. The interaction of RIS with the phenyl ring of Tyr204 proved essential for the maintenance of the isomerized enzyme-inhibitor complex. Studies with conformationally restricted analogues of RIS reaffirmed the importance of Thr201 in the formation of hydrogen bonds with N-BPs.In conclusion we have identified new features of FPPS inhibition by N-BPs and revealed unknown roles of the active site residues in catalysis and substrate binding

The oxytocin antagonist atosiban versus the beta-agonist terbutaline in the treatment of preterm labor - A randomized, double-blind, controlled study

Objective. To compare the efficacy and safety of atosiban and terbutaline for the inhibition of preterm labor