Siegfried Höfinger

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CerK (ceramide kinase) produces ceramide 1-phosphate, a sphingophospholipid with recognized signalling properties. It localizes to the Golgi complex and fractionates essentially between detergent-soluble and -insoluble fractions; however, the determinants are unknown. Here, we made a detailed mutagenesis study of the N-terminal PH domain (pleckstrin(More)
Deactivation routes of bright ππ* (La) and excimer charge transfer (CT) states have been mapped for two stacked quantum mechanical (CASPT2//CASSCF) adenines inside a solvated DNA double strand decamer (poly(dA)·poly(dT)) described at the molecular mechanics level. Calculations show that one carbon (C2) puckering is a common relaxation coordinate for both(More)
Class I cytokine receptors efficiently transfer activation signals from the extracellular space to the cytoplasm and play a dominant role in growth control and differentiation of human tissues. Although a significant body of literature is devoted to this topic, a consistent mechanistic picture for receptor activation in the membrane environment is still(More)
The accurate description of solvation effects is highly desirable in numerous computational chemistry applications. One widely used methodology treats the solvent as a uniform continuum ("implicit solvation"), and describes its net interaction with the solute by solving the Poisson-Boltzmann (PB) equation using the Boundary Element Method (BEM). These(More)
A parallel version of an optimization algorithm for arbitrary functions of arbitrary dimension N has been developed and tested on an IBM-Regatta HPC system equipped with 16 CPUs of Power4 type, each with 1.3 GHz clock frequency. The optimization algorithm follows a simplex-like stochastic search technique aimed at quasi-complete sampling of all the local(More)
The study of membrane proteins requires a proper consideration of the specific environment provided by the biomembrane. The compositional complexity of this environment poses great challenges to all experimental and theoretical approaches. In this article a rather simple theoretical concept is discussed for its ability to mimic the biomembrane. The(More)
Carbon nanotubes have been proposed to serve as nano-vehicles to deliver genetic or therapeutic material into the interior of cells because of their capacity to cross the cell membrane. A detailed picture of the molecular mode of action of such a delivery is, however, difficult to obtain because of the concealing effects of the cell membrane. Here we report(More)
Scientific applications do frequently suffer from limited compute performance. In this article, we investigate the suitability of specialized computer chips to overcome this limitation. An enhanced Poisson Boltzmann program is ported to the graphics processing unit and the application specific integrated circuit MDGRAPE-3 and resulting execution times are(More)
Lysozyme has been successfully used to solvate carbon nanotubes (CNT). Extensive molecular dynamics simulations show that 1) a favorite site of adsorption exists, 2) the protein-tube interaction region is located far from the active site, 3) two protein helices act as a tweezer that grips the nanotube, 4) a localized protein re-arrangement hides the tube(More)