Matrix processing peptidase of mitochondria

The mitochondrial processing peptidase (MPP) and the processing enhancing protein (PEP) cooperate in the proteolytic cleavage of matrix targeting sequences from nuclear-encoded mitochondrial precursor proteins. We have determined the cDNA sequence of Neurospora MPP after expression cloning. MPP appears to contain two domains of approximately equal size which are separated by a loop-like sequence. Considerable structural similarity exists to the recently sequenced yeast MPP as well as to Neurospora and yeast PEP. Four cysteine residues are conserved in Neurospora and yeast MPP. Inactivation of MPP can be achieved by using sulfhydryl reagents. MPP (but not PEP) depends on the presence of divalent metal ions for activity. Both MPP and PEP are synthesized as precursors containing matrix targeting signals which are processed during import into mitochondria by the mature forms of MPP and PEP

Lebenstatsachen : Geburt und Adoption bei Lessing und Kleist

Jedem Leser Kleists ist die Häufigkeit vertraut, mit der Geschlechtsverkehr, Zeugung, Schwangerschaft und Geburt im Zentrum seiner Werke stehen. Offensichtlichen Beispiele sind die beiden Komödien Der Zerbrochne Krug und Amphitryon sowie die Erzählungen Die Marquise von O... und Der Zweikampf. Ihnen ist eine (mehr oder weniger) hinter die Kulissen verlegte und in ihren Umständen dunkle sexuelle Begegnung gemeinsam, aus der sich die konfliktträchtige Handlung entwickelt, die von der Dynamik einer detektivischen Aufklärung angetrieben wird. Hierin erschöpft sie sich freilich nicht. Denn in dem Maße, in dem sich der faktische Tatbestand klärt und die Frage "wer mit wem unter welchen Umständen" schließlich beantwortet erscheint, vollzieht sich ein anderer und gegenläufiger Prozeß, der jenen blinden körperlichen Moment zum Gegenstand kultureller Bedeutungsstiftung macht und dem nackten Blick entzieht. Aufklärung und Verbergung, Enthüllen und Verhüllen bilden hier unauflöslich ineinander verschlungene Vorgänge. ..

Das Licht der Welt : Geburt und Bild in Goethes Faustdichtung

Der Aufsatz verfolgt die Thematik des Sehens und des Lichts im Faust und verknüpft sie mit der von der neueren Forschung herausgearbeiteten kulturanthropologischen Dimension der Dichtung. Die These ist, daß Faust sich vom kreatürlichen (vormodernen) Empfangen des Schöpfungslichts in die eigenproduzierte Welt einer künstlichen Helligkeit entfernt, bis er, erblindet, nur noch seine innere Vision der "neuesten Erde" übrigbehält. Von diesem mephistophelisch infizierten neuzeitlichen Prozeß sind die ästhetischen Bilder nicht abzutrennen, die andererseits die verlorene ´gebürtige´ Selbstverständlichkeit des Daseins unter der Voraussetzung neuzeitlicher Autonomie wiederzuholen versuchen. Das Dilemma einer ´ästhetischen Selbstbeschenkung´ des autonomen Subjekts mit seiner Geburt thematisiert Goethes Drama auch durch die Selbstreflexion seines theatralischen Mediums.The essay traces the thematics of seeing and light in Faust, drawing on the cultural-anthropological dimension of the play developed by recent research. It claims that Faust withdraws from the "natural" (pre-modern) light bestowed by creation into an artificially illuminated world of his own making until, having grown blind, he only retains his inner vision of the "newest earth." Inextricably connected to this process of modernity infected by Mephistopheles are the aesthetic images which, on the other hand, attempt to restore the lost self-evidence of existence under the premises of modern autonomy. Goethe´s drama also thematizes this dilemma of the autonomous subject who gives birth to himself in the art work through the self-reflection of the theatrical medium

Characterization of the mitochondrial processing peptidase of Neurospora crassa

The mitochondrial processing peptidase (MPP) of Neurospora crassa is constituted by an alpha- and a beta-subunit. We have purified alpha-MPP after expression in Escherichia coli while beta-MPP was purified from mitochondria. A fusion protein between precytochrome b2 and mouse dihydrofolate reductase was expressed in E. coli, and the purified protein was used as substrate for MPP. Both subunits of MPP are required for processing. MPP removes the matrix targeting signal of cytochrome b2 by a single cut, and the resulting presequence peptide is 31 amino acid residues in length. It acts as a competitive inhibitor of processing but has a approximately 30-fold lower affinity for MPP than the preprotein. Competition assays show that MPP recognizes the COOH- terminal portion of the presequence of cytochrome b2 rather than the NH2-terminal part which has the potential to form an amphiphilic helix. Substitution of arginine in position -2 of the matrix targeting sequence of cytochrome b2 prevents processing but not import of a chimeric precursor. Substitution of the tyrosyl residue in position +1 also prevents processing, indicating that MPP interacts with sequences COOH-terminal to the cleavage site. Non-cleavable preprotein is still recognized by MPP. Our data suggest that processing peptidase and import machinery recognize distinct structural elements in preproteins which, however, can be overlapping

A Note on Multilevel Based Error Estimation

By employing the infinite multilevel representation of the residual, we derive computable bounds to estimate the distance of finite element approximations to the solution of the Poisson equation. If the finite element approximation is a Galerkin solution, the derived error estimator coincides with the standard element and edge based estimator. If Galerkin orthogonality is not satisfied, then the discrete residual additionally appears in terms of the BPX preconditioner. As a by-product of the present analysis, conditions are derived such that the hierarchical error estimation is reliable and efficient

Integrating the SAP R/3 System into an MIS Program

In this tutorial, the authors share their experience with integrating the SAP R/3 System into their curriculum so that an attendee can walk away knowing how to approach the tasks at his or her university. The authors are part of a team of faculty whose ultimate objective is to develop a cross-functional business school curriculum. An overview of the business plan is presented, some details regarding systems administration is provided, and the majority of the time is spent on identifying opportunities for enriching an MIS program. This paper does not address curriculum content issues but provides information on how a commercial ERP system (i.e., the SAP R/3 System) can be effectively utilized in an MIS program. The opinions expressed here are solely those of the authors

Using ERP Systems in Education

Enterprise Resource Planning systems are the new solution to business systems. These systems provide comprehensive business functionality in an integrated fashion using a state-of-the-art IT architecture. This trend towards enterprise systems in large and mid-sized organizations has a significant impact on IS careers paths. Enterprise systems essentially change fundamental business work processes thus implying that the system that supports these processes, and the design and development of these systems, also changed. Yet, most IS curricula do not provide significant coverage of ERP concepts, nor do they graduate students who are knowledgeable about these systems and the impact that these systems have on industry. This paper identifies opportunities for incorporating the ERP body of knowledge into an IS program. The general spirit of the paper is that of experiential learning. That is, this paper focuses on curriculum that is enriched through the hands-on experience gained by students working on a real ERP system. The paper also discusses related topics such as costs and critical success factors