@article{AkhoonSinghVarshneyetal.2014, author = {Akhoon, Bashir A. and Singh, Krishna P. and Varshney, Megha and Gupta, Shishir K. and Shukla, Yogeshwar and Gupta, Shailendra K.}, title = {Understanding the Mechanism of Atovaquone Drug Resistance in Plasmodium falciparum Cytochrome b Mutation Y268S Using Computational Methods}, series = {PLOS ONE}, volume = {9}, journal = {PLOS ONE}, number = {10}, doi = {10.1371/journal.pone.0110041}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-114882}, pages = {e110041}, year = {2014}, abstract = {The rapid appearance of resistant malarial parasites after introduction of atovaquone (ATQ) drug has prompted the search for new drugs as even single point mutations in the active site of Cytochrome b protein can rapidly render ATQ ineffective. The presence of Y268 mutations in the Cytochrome b (Cyt b) protein is previously suggested to be responsible for the ATQ resistance in Plasmodium falciparum (P. falciparum). In this study, we examined the resistance mechanism against ATQ in P. falciparum through computational methods. Here, we reported a reliable protein model of Cyt bc1 complex containing Cyt b and the Iron-Sulphur Protein (ISP) of P. falciparum using composite modeling method by combining threading, ab initio modeling and atomic-level structure refinement approaches. The molecular dynamics simulations suggest that Y268S mutation causes ATQ resistance by reducing hydrophobic interactions between Cyt bc1 protein complex and ATQ. Moreover, the important histidine contact of ATQ with the ISP chain is also lost due to Y268S mutation. We noticed the induced mutation alters the arrangement of active site residues in a fashion that enforces ATQ to find its new stable binding site far away from the wild-type binding pocket. The MM-PBSA calculations also shows that the binding affinity of ATQ with Cyt bc1 complex is enough to hold it at this new site that ultimately leads to the ATQ resistance.}, language = {en} } @article{KatoLuRapaportetal.2013, author = {Kato, Hiroki and Lu, Qiping and Rapaport, Doron and Kozjak-Pavlovic, Vera}, title = {Tom70 Is Essential for PINK1 Import into Mitochondria}, series = {PLoS ONE}, volume = {8}, journal = {PLoS ONE}, number = {3}, doi = {10.1371/journal.pone.0058435}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131061}, pages = {e58435}, year = {2013}, abstract = {PTEN induced kinase 1 (PINK1) is a serine/threonine kinase in the outer membrane of mitochondria (OMM), and known as a responsible gene of Parkinson's disease (PD). The precursor of PINK1 is synthesized in the cytosol and then imported into the mitochondria via the translocase of the OMM (TOM) complex. However, a large part of PINK1 import mechanism remains unclear. In this study, we examined using cell-free system the mechanism by which PINK1 is targeted to and assembled into mitochondria. Surprisingly, the main component of the import channel, Tom40 was not necessary for PINK1 import. Furthermore, we revealed that the import receptor Tom70 is essential for PINK1 import. In addition, we observed that although PINK1 has predicted mitochondrial targeting signal, it was not processed by the mitochondrial processing peptidase. Thus, our results suggest that PINK1 is imported into mitochondria by a unique pathway that is independent of the TOM core complex but crucially depends on the import receptor Tom70.}, language = {en} } @article{WaelbroeckCamusTastenoyetal.1993, author = {Waelbroeck, M. and Camus, J. and Tastenoy, M. and Lambrecht, G. and Mutschler, E. and Kropfgans, M. and Sperlich, J. and Wiesenberger, F. and Tacke, R. and Christophe, J.}, title = {Thermodynamics of antagonist binding to rat muscarinic \(M_2\) receptors: antimuscarinics of the pridinol, sila-pridinol, diphenidol and sila-diphenidol type}, series = {British Journal of Pharmacology}, volume = {109}, journal = {British Journal of Pharmacology}, number = {2}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-128439}, pages = {360-370}, year = {1993}, abstract = {1 We studied the effect of temperature on the binding to rat heart \(M_2\) muscarinic receptors of antagonists related to the carbon/silicon pairs pridinol/sila-pridinol and diphenidol/sila-diphenidol (including three germanium compounds) and six structurally related pairs of enantiomers [(R)- and (S)-procyclidine, (R)- and (S)-trihexyphenidyl, (R)- and (S)-tricyclamol, (R)- and (S)-trihexyphenidyl methiodide, (R)- and (S)-hexahydro-diphenidol and (R)- and (S)-hexbutinol]. Binding affinities were determined in competition experiments using \([^3H]\)-N-methyl-scopolamine chloride as radioligand. The reference drugs were scopolamine and N-methyl-scopolamine bromide. 2 The affinity of the antagonists either increased or decreased with temperature, van 't Hoff plots were linear in the 278-310°K temperature range. Binding of all antagonists was entropy driven. Enthalpy changes varied from large negative values (down to \(-29 kJ mol^{-1}\)) to large positive values (up to \(+ 30 kJ mol^{-1}\)). 3 (R)-configurated drugs had a 10 to 100 fold greater affinity for \(M_2\) receptors than the corresponding (S)-enantiomers. Enthalpy and entropy changes of the respective enantiomers were different but no consistent pattern was observed. 4 When silanols \((R_3SiOH)\) were compared to carbinols \((R_3COH)\), the affinity increase caused by C/Si exchange varied between 3 and 10 fold for achiral drugs but was negligible in the case of chiral drugs. Silanols induced more favourable enthalpy and less favourable entropy changes than the corresponding carbinols when binding. Organogermanium compounds \((R_4Ge)\) when compared to their silicon counterparts (R4Si) showed no significant difference in affinity as well as in enthalpy and entropy changes. 5 Exchange of a cyclohexyl by a phenyl moiety was associated with an increase or a decrease in drug affinity (depending on the absolute configuration in the case of chiral drugs) and generally also with a more favourable enthalpy change and a less favourable entropy change of drug binding. 6 Replacement of a pyrrolidino by a piperidino group and increasing the length of the alkylene chain bridging the amino group and the central carbon or silicon atom were associated with either an increase or a decrease of entropy and enthalpy changes of drug binding. However, there was no clear correlation between these structural variations and the thermodynamic effects. 7 Taken together, these results suggest that hydrogen bond-forming OH groups and, to a lesser extent, polarizable phenyl groups contribute significantly to the thermodynamics of interactions between these classes of muscarinic antagonists and \(M_2\) muscarinic receptors.}, language = {en} } @article{WilleSchuemannWreeetal.2015, author = {Wille, Michael and Sch{\"u}mann, Antje and Wree, Andreas and Kreutzer, Michael and Glocker, Michael O. and Mutzbauer, Grit and Schmitt, Oliver}, title = {The Proteome Profiles of the Cerebellum of Juvenile, Adult and Aged Rats-An Ontogenetic Study}, series = {International Journal of Molecular Sciences}, volume = {16}, journal = {International Journal of Molecular Sciences}, doi = {10.3390/ijms160921454}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-151347}, pages = {21454 -- 21485}, year = {2015}, abstract = {In this study, we searched for proteins that change their expression in the cerebellum (Ce) of rats during ontogenesis. This study focuses on the question of whether specific proteins exist which are differentially expressed with regard to postnatal stages of development. A better characterization of the microenvironment and its development may result from these study findings. A differential two-dimensional polyacrylamide gel electrophoresis (2DE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis of the samples revealed that the number of proteins of the functional classes differed depending on the developmental stages. Especially members of the functional classes of biosynthesis, regulatory proteins, chaperones and structural proteins show the highest differential expression within the analyzed stages of development. Therefore, members of these functional protein groups seem to be involved in the development and differentiation of the Ce within the analyzed development stages. In this study, changes in the expression of proteins in the Ce at different postnatal developmental stages (postnatal days (P) 7, 90, and 637) could be observed. At the same time, an identification of proteins which are involved in cell migration and differentiation was possible. Especially proteins involved in processes of the biosynthesis and regulation, the dynamic organization of the cytoskeleton as well as chaperones showed a high amount of differentially expressed proteins between the analyzed dates.}, language = {en} } @article{ScholzGehringGuanetal.2015, author = {Scholz, Nicole and Gehring, Jennifer and Guan, Chonglin and Ljaschenko, Dmitrij and Fischer, Robin and Lakshmanan, Vetrivel and Kittel, Robert J. and Langenhan, Tobias}, title = {The adhesion GPCR Latrophilin/CIRL shapes mechanosensation}, series = {Cell Reports}, volume = {11}, journal = {Cell Reports}, doi = {10.1016/j.celrep.2015.04.008}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-148626}, pages = {866-874}, year = {2015}, abstract = {G-protein-coupled receptors (GPCRs) are typically regarded as chemosensors that control cellular states in response to soluble extracellular cues. However, the modality of stimuli recognized through adhesion GPCR (aGPCR), the second largest class of the GPCR superfamily, is unresolved. Our study characterizes the Drosophila aGPCR Latrophilin/dCirl, a prototype member of this enigmatic receptor class. We show that dCirl shapes the perception of tactile, proprioceptive, and auditory stimuli through chordotonal neurons, the principal mechanosensors of Drosophila. dCirl sensitizes these neurons for the detection of mechanical stimulation by amplifying their input-output function. Our results indicate that aGPCR may generally process and modulate the perception of mechanical signals, linking these important stimuli to the sensory canon of the GPCR superfamily.}, language = {en} } @article{MockeWellerFringsetal.2020, author = {Mocke, Viola and Weller, Lisa and Frings, Christian and Rothermund, Klaus and Kunde, Wilfried}, title = {Task relevance determines binding of effect features in action planning}, series = {Attention, Perception, \& Psychophysics}, volume = {82}, journal = {Attention, Perception, \& Psychophysics}, issn = {1943-3921}, doi = {10.3758/s13414-020-02123-x}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-231906}, pages = {3811-3831}, year = {2020}, abstract = {Action planning can be construed as the temporary binding of features of perceptual action effects. While previous research demonstrated binding for task-relevant, body-related effect features, the role of task-irrelevant or environment-related effect features in action planning is less clear. Here, we studied whether task-relevance or body-relatedness determines feature binding in action planning. Participants planned an action A, but before executing it initiated an intermediate action B. Each action relied on a body-related effect feature (index vs. middle finger movement) and an environment-related effect feature (cursor movement towards vs. away from a reference object). In Experiments 1 and 2, both effects were task-relevant. Performance in action B suffered from partial feature overlap with action A compared to full feature repetition or alternation, which is in line with binding of both features while planning action A. Importantly, this cost disappeared when all features were available but only body-related features were task-relevant (Experiment 3). When only the environment-related effect of action A was known in advance, action B benefitted when it aimed at the same (vs. a different) environment-related effect (Experiment 4). Consequently, the present results support the idea that task relevance determines whether binding of body-related and environment-related effect features takes place while the pre-activation of environment-related features without binding them primes feature-overlapping actions.}, language = {en} } @article{MuellerWindhofMaximovetal.2013, author = {M{\"u}ller, Sara and Windhof, Indra M. and Maximov, Vladimir and Jurkowski, Tomasz and Jeltsch, Albert and F{\"o}rstner, Konrad U. and Sharma, Cynthia M. and Gr{\"a}f, Ralph and Nellen, Wolfgang}, title = {Target recognition, RNA methylation activity and transcriptional regulation of the Dictyostelium discoideum Dnmt2-homologue (DnmA)}, series = {Nucleic Acids Research}, volume = {41}, journal = {Nucleic Acids Research}, number = {18}, issn = {1362-4962}, doi = {10.1093/nar/gkt634}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-123149}, pages = {8615-8627}, year = {2013}, abstract = {Although the DNA methyltransferase 2 family is highly conserved during evolution and recent reports suggested a dual specificity with stronger activity on transfer RNA (tRNA) than DNA substrates, the biological function is still obscure. We show that the Dictyostelium discoideum Dnmt2-homologue DnmA is an active tRNA methyltransferase that modifies C38 in \(tRNA^{Asp(GUC)}\) in vitro and in vivo. By an ultraviolet-crosslinking and immunoprecipitation approach, we identified further DnmA targets. This revealed specific tRNA fragments bound by the enzyme and identified \(tRNA^{Glu(CUC/UUC)}\) and \(tRNA^{Gly(GCC)}\) as new but weaker substrates for both human Dnmt2 and DnmA in vitro but apparently not in vivo. Dnmt2 enzymes form transient covalent complexes with their substrates. The dynamics of complex formation and complex resolution reflect methylation efficiency in vitro. Quantitative PCR analyses revealed alterations in dnmA expression during development, cell cycle and in response to temperature stress. However, dnmA expression only partially correlated with tRNA methylation in vivo. Strikingly, dnmA expression in the laboratory strain AX2 was significantly lower than in the NC4 parent strain. As expression levels and binding of DnmA to a target in vivo are apparently not necessarily accompanied by methylation, we propose an additional biological function of DnmA apart from methylation.}, language = {en} } @phdthesis{Ackermann2010, author = {Ackermann, Matthias}, title = {Studien zum Verhalten von Anthocyanen aus Heidelbeeren im Humanstoffwechsel - Stabilisierung und Bindung durch Proteine}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-53336}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2010}, abstract = {Identifizierung und Strukturaufkl{\"a}rung von Anthocyanen und ihrer Metabolite erfolgten mit Hilfe der mittels Hochleistungsfl{\"u}ssigchromatographie-Diodenarray-Detektion-Elektro-spray-Tan¬dem¬massen¬spektrometrie (HPLC-DAD-ESI-MS/MS). Quantitative Analysen wurden via HPLC-DAD durchgef{\"u}hrt. Die hierzu erforderlichen Referenzverbindungen wurden mittels pr{\"a}parativer HPLC aus Heidelbeeren isoliert (Reinheit zwischen 85,8\% und 99,4\%). Der Gehalt an Anthocyanen in den untersuchten Heidelbeerfr{\"u}chten lag bei 6 g/kg. Bez{\"u}glich der mengen¬m{\"a}ßigen Verteilung dominierten Delphinidin- und Cyanidin¬glykoside vor den Glykosiden von Malvidin, Petunidin und Peonidin. Als konjugierte Zucker¬reste kamen vor allem Glukose und Galaktose vor, der Gehalt an Arabinosiden war weit geringer. Bei oraler Aufnahme erfolgt ein erster Kontakt der Anthocyane mit Speichel. Daher wurde dessen Wirkung auf die Heidelbeeranthocyane in ex vivo-Studien {\"u}ber einen (unphysio-logisch langen) Zeitraum von bis zu 30 Minuten untersucht. Dabei konnte wurde ins-besondere der Einfluß des pH-Wertes auf die Stabilit{\"a}t der Anthocyane aufgezeigt werden. Zur Simulation des Verhaltens von Anthocyanen im Magen wurden die einzelnen Heidelbeeranthocyane mit k{\"u}nstlichem Magensaft (pH 1,81) {\"u}ber vier Stunden inkubiert. Hier erwiesen sich alle untersuchten Verbindungen als stabil. Die anschließend von uns mit simuliertem Duodenalsekret (pH 7,2) {\"u}ber einen Zeitraum von 24 Stunden durchgef{\"u}hrten Studien zeigten, dass die Anthocyane unterschiedlich starken Modifizierungen unterlagen. Unter den schwach alkalischen Bedingungen wurden vor allem die Glykoside des Delphinidins schnell abgebaut, aber auch die {\"u}brigen Anthocyane erwiesen sich unter diesen Bedingungen als nicht stabil; nach 24 h war kein Anthocyan mehr nachweisbar. Um die Metabolisierungsvorg{\"a}nge der Anthocyane im D{\"u}nn- und Dickdarm zu untersuchen, wurden ex vivo-Inkubationen jeweils mit frischem Ileo- bzw. Kolo¬stoma-beutel¬inhalt durchgef{\"u}hrt. W{\"a}hrend die Abbaugeschwindigkeit in der ilealen Fl{\"u}ssigkeit vor allem von der pH-Stabilit{\"a}t des Aglykons abh{\"a}nig war, konnten im Dickdarm einzig die Arabinoside nach einer Stunde noch alle in geringen Konzentrationen identifiziert werden. Die meisten Glukoside und Galaktoside waren zu diesem Zeitpunkt schon vollst{\"a}ndig abgebaut. Da im Darm von einer hydrolytischen Spaltung der Anthocyane in Anthocyanidin und Zucker ausgegangen wird, wurde die Metabolisierung von Anthocyanidinen unter physio-logischen pH-Bedingungen untersucht. Neben der jeweiligen Spaltung in das Benzoe¬s{\"a}ure-derivat des B-Ringes sowie Phloroglucinessigs{\"a}ure traten verschiedene Poly¬merisierungs¬-produkte auf, deren Strukturen nicht aufgekl{\"a}rt werden konnten. In einer weiteren Versuchsreihe wurde die renale Ausscheidung von Anthocyanen bei Ileostomieprobanden nach oraler Applikation von 300 g Heidelbeeren {\"u}ber einen Zeitraum von acht Stunden untersucht. Es zeigte sich, dass ein Stoma des terminalen Ileums keinen Einfluss auf die Absorption und Metabolisierung der Anthocyane hatte. Die Bilanzierung der Anthocyane im Urin erfolgte als {\"A}quvalente von Malvidin-3-O-glukosid, da nicht alle Anthocyanmetabolite zur Verf{\"u}gung standen. Der Zeitpunkt der maximalen renalen Anthocyanausscheidung sowie die Menge der ausgeschiedenen Anthocyane waren starken interindividuellen Schwankungen unterworfen. Das Aus¬sscheidungs¬maximum (tmax) lag zwischen 0,5 und zwei Stunden. Bei der ausge¬schiedenen Menge wurden Werte zwischen 0,007\% und 0.019\% der auf¬ge¬nommenen Anthocyane ermittelt. Aufgrund der literaturbekannten Unterschiede zwischen den in Serum und Urin gefunden Anthocyanmengen ist davon auszugehen, dass es nach Anthocyanverzehr zu Inter-aktionen mit Proteinen in Blut oder Geweben kommt. Mittels Blutfraktionierung wurde das humane Serumalbumin (HSA) als wichtigster Bindungspartner der Anthocyane im Blut identifiziert. Anhand spektroskopischer Methoden war es m{\"o}glich, die Bindungs¬parameter zu berechnen. Als Bindungsort wurde der hydrophile Eingang der lipophilen Warfarin-Bindungstasche in der Subdom{\"a}ne IIA des HSA-Molek{\"u}ls mittels "molecular modelling" identifiziert. Nasschemische Untersuchungen ergaben, dass die Bindung der Anthocyane an HSA diese vor ihrem pH-abh{\"a}ngigen Abbau sch{\"u}tzt. Eine signifikante Herab¬setzung der chemischen Abbaugeschwindig¬keit konnte auch f{\"u}r bovines Serumalbumin beobachtet werden. Diese Erkenntnis ließ sich auf andere, mit dem HSA-Molek{\"u}l nicht strukurverwandte lebensmittelrelevante Albumine {\"u}bertragen. So zeigten Anthocyane große Stabilit{\"a}t in Milch und Eiklar, wobei die Stabilisierung auf eine Wechselwirkung mit den Proteinen Laktalbumin und Ovalbumin zur{\"u}ckgef{\"u}hrt werden konnte. Die in dieser Arbeit erlangten Erkenntnisse hinsichtlich Absorption, Metabolisierung und systemischer Verf{\"u}gbarkeit im menschlichen Organismus leisten einen Beitrag zum besseren Verst{\"a}ndnis der Wirkungen von Anthocyanen. Die neuen Erkenntnisse der Protein¬bindung sind vor allem f{\"u}r die Bewertung der Verf{\"u}gbarkeit der Anthocyane in humanem Gewebe relevant.}, subject = {Heidelbeere}, language = {de} } @article{VolceanovHerbstBiniosseketal.2014, author = {Volceanov, Larisa and Herbst, Katharina and Biniossek, Martin and Schilling, Oliver and Haller, Dirk and N{\"o}lke, Thilo and Subbarayal, Prema and Rudel, Thomas and Zieger, Barbara and H{\"a}cker, Georg}, title = {Septins Arrange F-Actin-Containing Fibers on the Chlamydia trachomatis Inclusion and Are Required for Normal Release of the Inclusion by Extrusion}, series = {MBIO}, volume = {5}, journal = {MBIO}, number = {5}, issn = {2150-7511}, doi = {10.1128/mBio.01802-14}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-115421}, pages = {e01802-14}, year = {2014}, abstract = {Chlamydia trachomatis is an obligate intracellular human pathogen that grows inside a membranous, cytosolic vacuole termed an inclusion. Septins are a group of 13 GTP-binding proteins that assemble into oligomeric complexes and that can form higher-order filaments. We report here that the septins SEPT2, -9, -11, and probably -7 form fibrillar structures around the chlamydial inclusion. Colocalization studies suggest that these septins combine with F actin into fibers that encase the inclusion. Targeting the expression of individual septins by RNA interference (RNAi) prevented the formation of septin fibers as well as the recruitment of actin to the inclusion. At the end of the developmental cycle of C. trachomatis, newly formed, infectious elementary bodies are released, and this release occurs at least in part through the organized extrusion of intact inclusions. RNAi against SEPT9 or against the combination of SEPT2/7/9 substantially reduced the number of extrusions from a culture of infected HeLa cells. The data suggest that a higher-order structure of four septins is involved in the recruitment or stabilization of the actin coat around the chlamydial inclusion and that this actin recruitment by septins is instrumental for the coordinated egress of C. trachomatis from human cells. The organization of F actin around parasite-containing vacuoles may be a broader response mechanism of mammalian cells to the infection by intracellular, vacuole-dwelling pathogens. IMPORTANCE Chlamydia trachomatis is a frequent bacterial pathogen throughout the world, causing mostly eye and genital infections. C. trachomatis can develop only inside host cells; it multiplies inside a membranous vacuole in the cytosol, termed an inclusion. The inclusion is covered by cytoskeletal "coats" or "cages," whose organization and function are poorly understood. We here report that a relatively little-characterized group of proteins, septins, is required to organize actin fibers on the inclusion and probably through actin the release of the inclusion. Septins are a group of GTP-binding proteins that can organize into heteromeric complexes and then into large filaments. Septins have previously been found to be involved in the interaction of the cell with bacteria in the cytosol. Our observation that they also organize a reaction to bacteria living in vacuoles suggests that they have a function in the recognition of foreign compartments by a parasitized human cell.}, language = {en} } @article{KrehanHeubeckMenzeletal.2012, author = {Krehan, Mario and Heubeck, Christian and Menzel, Nicolas and Seibel, Peter and Sch{\"o}n, Astrid}, title = {RNase MRP RNA and RNase P activity in plants are associated with a Pop1p containing complex}, series = {Nucleic Acids Research}, volume = {40}, journal = {Nucleic Acids Research}, number = {16}, doi = {10.1093/nar/gks476}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130648}, pages = {7956- 7966}, year = {2012}, abstract = {RNase P processes the 5'-end of tRNAs. An essential catalytic RNA has been demonstrated in Bacteria, Archaea and the nuclei of most eukaryotes; an organism-specific number of proteins complement the holoenzyme. Nuclear RNase P from yeast and humans is well understood and contains an RNA, similar to the sister enzyme RNase MRP. In contrast, no protein subunits have yet been identified in the plant enzymes, and the presence of a nucleic acid in RNase P is still enigmatic. We have thus set out to identify and characterize the subunits of these enzymes in two plant model systems. Expression of the two known Arabidopsis MRP RNA genes in vivo was verified. The first wheat MRP RNA sequences are presented, leading to improved structure models for plant MRP RNAs. A novel mRNA encoding the central RNase P/MRP protein Pop1p was identified in Arabidopsis, suggesting the expression of distinct protein variants from this gene in vivo. Pop1p-specific antibodies precipitate RNase P activity and MRP RNAs from wheat extracts. Our results provide evidence that in plants, Pop1p is associated with MRP RNAs and with the catalytic subunit of RNase P, either separately or in a single large complex.}, language = {en} }