Filtyp
Nanowire array solar cells show intrinsic light trapping and absorption enhancement properties due to the diffraction and optical resonances. Here, we report the effect of varying incidence angle on the performance of GaAs nanowire array solar cells. We provide experimental evidence that nanowire array solar cells are highly efficient at gathering diffuse or tilted incident light, even at very hig
Reality isn’t what it appears to be. Contexts are not always clear and visible. People don’t always say what they really mean. And they don’t always mean what they say. When life is your stage manager, anything can happen. I often say, life is hard, my head is harder. Making documentaries is not for the faint-hearted.This PhD project explores creative processes and parallel realities in documentar
Menkes disease (MD) is caused by mutations in ATP7A, encoding a copper-transporting P-type ATPase which exhibits copper-dependent trafficking. ATP7A is found in the Trans-Golgi Network (TGN) at low copper concentrations, and in the post-Golgi compartments and the plasma membrane at higher concentrations. Here we have analyzed the effect of 36 ATP7A missense mutations identified in phenotypically d
To obtain an electron-density map from a macromolecular crystal the phase problem needs to be solved, which often involves the use of heavy-atom derivative crystals and concomitant heavy-atom substructure determination. This is typically performed by dual-space methods, direct methods or Patterson-based approaches, which however may fail when only poorly diffracting derivative crystals are availab
Cells regulate copper levels tightly to balance the biogenesis and integrity of copper centers in vital enzymes against toxic levels of copper. PIB -type Cu(+)-ATPases play a central role in copper homeostasis by catalyzing the selective translocation of Cu(+) across cellular membranes. Crystal structures of a copper-free Cu(+)-ATPase are available, but the mechanism of Cu(+) recognition, binding,
P-type ATPases from the P4 subfamily (P4-ATPases) are energy-dependent transporters, which are thought to establish lipid asymmetry in eukaryotic cell membranes. Together with their Cdc50 accessory subunits, P4-ATPases couple ATP hydrolysis to lipid transport from the exoplasmic to the cytoplasmic leaflet of plasma membranes, late Golgi membranes, and endosomes. To gain insights into the structure
Heavy metals in cells are typically regulated by PIB-type ATPases. The first structure of the class, a Cu(+)-ATPase from Legionella pneumophila (LpCopA), outlined a copper transport pathway across the membrane, which was inferred to be occluded. Here we show by molecular dynamics simulations that extracellular water solvated the transmembrane (TM) domain, results indicative of a Cu(+)-release path
The Na(+), K(+)-adenosine triphosphatase (ATPase) maintains the electrochemical gradients of Na(+) and K(+) across the plasma membrane--a prerequisite for electrical excitability and secondary transport. Hitherto, structural information has been limited to K(+)-bound or ouabain-blocked forms. We present the crystal structure of a Na(+)-bound Na(+), K(+)-ATPase as determined at 4.3 Å resolution. Co
The transient receptor potential vanilloid 3 (TRPV3) cation channel is widely expressed in human tissues and has been shown to be activated by mild temperatures or chemical ligands. In spite of great progress in the TRP-channel characterization, very little is known about their structure and interactions with other proteins at the atomic level. This is mainly caused by difficulties in obtaining fu
The human copper exporters ATP7A and ATP7B contain domains common to all P-type ATPases as well as class-specific features such as six sequential heavy-metal binding domains (HMBD1-HMBD6) and a type-specific constellation of transmembrane helices. Despite the medical significance of ATP7A and ATP7B related to Menkes and Wilson diseases, respectively, structural information has only been available
P-type ATPases perform active transport of various compounds across biological membranes and are crucial for ion homeostasis and the asymmetric composition of lipid bilayers. Although their functional cycle share principles of phosphoenzyme intermediates, P-type ATPases also show subclass-specific sequence motifs and structural elements that are linked to transport specificity and mechanistic modu
Heavy-metal homeostasis and detoxification is crucial for cell viability. P-type ATPases of the class IB (PIB) are essential in these processes, actively extruding heavy metals from the cytoplasm of cells. Here we present the structure of a PIB-ATPase, a Legionella pneumophila CopA Cu(+)-ATPase, in a copper-free form, as determined by X-ray crystallography at 3.2 Å resolution. The structure indica
Ca(2+)-ATPases are ATP-driven membrane pumps that are responsible for the transport of Ca(2+) ions across the membrane. The Listeria monocytogenes Ca(2+)-ATPase LMCA1 has been crystallized in the Ca(2+)-free state stabilized by AlF(4)(-), representing an occluded E2-P(i)-like state. The crystals belonged to space group P2(1)2(1)2 and a complete data set extending to 4.3 Å resolution was collected.
We have characterized a putative Ca(2+)-ATPase from the pathogenic bacterium Listeria monocytogenes with the locus tag lmo0841. The purified and detergent-solubilized protein, which we have named Listeria monocytogenes Ca(2+)-ATPase 1 (LMCA1), performs a Ca(2+)-dependent ATP hydrolysis and actively transports Ca(2+) after reconstitution in dioleoylphosphatidyl-choline vesicles. Despite a high sequ
Proteorhodopsin is an integral membrane light-harvesting proton pump that is found in bacteria distributed throughout global surface waters. Here, we present a protocol for functional in vitro production of pR using a commercial cell-free synthesis system yielding 1.0mg purified protein per milliliter of cell lysate. We also present an optimized protocol for in vivo over-expression of pR in Escher
Bacterial drug resistance is a serious concern for human health. Multidrug efflux pumps export a broad variety of substrates out of the cell and thereby convey resistance to the host. In Escherichia coli, the AcrB:AcrA:TolC efflux complex forms a principal transporter for which structures of the individual component proteins have been determined in isolation. Here, we present the X-ray structure o
Liquid phase time-resolved x-ray diffraction with 100 ps resolution has recently emerged as a powerful technique for probing the structural dynamics of transient photochemical species in solution. It is intrinsic to the method, however, that a structural signal is observed not only from the photochemical of interest but also from the embedding solvent matrix. To experimentally characterize the x-r
