190 research outputs found
Students' Wage Expectations in Germany - New Evidence considering Tax Adjusted Estimates
This paper uses a rich dataset derived from a three-year survey to gain insights about the informational background of University applicants. We analyze the extent to which students expectations of their starting and future salary depend on different characteristics. More precisely, the paper investigates whether students with different backgrounds tend towards making larger or smaller errors when estimating salaries. The results point out that students salary estimates are heterogeneous and that this variation is correlated with individual traits and chosen subjects. Overall, students substantially underestimate actual starting salaries by about 20 percent. However, a prime finding of this paper is that estimation errors are highly attributable to students misconception of the German progressive income tax system. Correcting for the erroneous gross-net conversion, we find applicants to have a quite correct idea about what salaries to expect in the future. Overall, applicants adjusted expectations are in line with labor market outcomes. However, expectations remain strongly correlated with personal traits
Single-stranded DNA-binding protein of Deinococcus radiodurans: a biophysical characterization
The highly conserved bacterial single-stranded DNA-binding (SSB) proteins play an important role in DNA replication, repair and recombination and are essential for the survival of the cell. They are functional as tetramers, in which four OB(oligonucleotide/oligosaccharide binding)-folds act as DNA-binding domains. The protomer of the SSB protein from the extremely radiation-resistant organism Deinococcus radiodurans (DraSSB) has twice the size of the other bacterial SSB proteins and contains two OB-folds. Using analytical ultracentrifugation, we could show that DraSSB forms globular dimers with some protrusions. These DraSSB dimers can interact with two molecules of E.coli DNA polymerase III χ subunit. In fluorescence titrations with poly(dT) DraSSB bound 47–54 nt depending on the salt concentration, and fluorescence was quenched by more than 75%. A distinct low salt binding mode as for EcoSSB was not observed for DraSSB. Nucleic acid binding affinity, rate constant and association mechanism are quite similar for EcoSSB and DraSSB. In a complementation assay in E.coli, DraSSB took over the in vivo function of EcoSSB. With DraSSB behaving almost identical to EcoSSB the question remains open as to why dimeric SSB proteins have evolved in the Thermus group of bacteria
Template and Temperature Controlled Polymorph Formation in Squaraine Thin Films
Controlling the polymorph formation in organic semiconductor thin films by
the choice of substrate and deposition temperature is a key factor for targeted
device performance. Small molecular semiconductors such as the quadrupolar
donor-acceptor-donor (D-A-D) type squaraine compounds allow both solution and
vapor phase deposition methods. A prototypical anilino squaraine with branched
butyl chains as terminal functionalization (SQIB) has been considered for
photovoltaic applications due to its broad absorption within the visible to
deep-red spectral range. Its opto-electronic properties depend on the formation
of the two known polymorphs adopting a monoclinic and orthorhombic crystal
phase. Both phases emerge with a strongly preferred out-of-plane and rather
random in-plane orientation in spincasted thin films depending on subsequent
thermal annealing. Upon vapor deposition on dielectric and conductive
substrates, such as silicon dioxide, potassium chloride, graphene and gold, the
polymorph expression depends on the choice of growth substrate. In all cases
the same pronounced out-of-plane orientation is adopted, but with a surface
templated in-plane alignment in case of crystalline substrates. Combining X-ray
diffraction, atomic force microscopy, ellipsometry and polarized
spectro-microscopy we identify the processing dependent evolution of the
crystal phases, correlating morphology and molecular orientations within the
textured SQIB films.Comment: 10 pages, 7 figure
Protein translocation channel of mitochondrial inner membrane and matrix-exposed import motor communicate via two-domain coupling protein
The majority of mitochondrial proteins are targeted to mitochondria by N-terminal presequences and use the TIM23 complex for their translocation across the mitochondrial inner membrane. During import, translocation through the channel in the inner membrane is coupled to the ATP-dependent action of an Hsp70-based import motor at the matrix face. How these two processes are coordinated remained unclear. We show here that the two domain structure of Tim44 plays a central role in this process. The N-terminal domain of Tim44 interacts with the components of the import motor, whereas its C-terminal domain interacts with the translocation channel and is in contact with translocating proteins. Our data suggest that the translocation channel and the import motor of the TIM23 complex communicate through rearrangements of the two domains of Tim44 that are stimulated by translocating proteins
3D structure of Thermus aquaticus single-stranded DNA–binding protein gives insight into the functioning of SSB proteins
In contrast to the majority of tetrameric SSB proteins, the recently discovered SSB proteins from the Thermus/Deinoccus group form dimers. We solved the crystal structures of the SSB protein from Thermus aquaticus (TaqSSB) and a deletion mutant of the protein and show the structure of their ssDNA binding domains to be similar to the structure of tetrameric SSBs. Two conformations accompanied by proline cis–trans isomerization are observed in the flexible C-terminal region. For the first time, we were able to trace 6 out of 10 amino acids at the C-terminus of an SSB protein. This highly conserved region is essential for interaction with other proteins and we show it to adopt an extended conformation devoid of secondary structure. A model for binding this region to the χ subunit of DNA polymerase III is proposed. It explains at a molecular level the reason for the ssb113 phenotype observed in Escherichia coli
Structural and biochemical characterization of the cell fate determining nucleotidyltransferase fold protein MAB21L1
The exceptionally conserved metazoan MAB21 proteins are implicated in cell fate decisions and share considerable sequence homology with the cyclic GMP-AMP synthase. cGAS is the major innate immune sensor for cytosolic DNA and produces the second messenger 2'-5', 3'-5' cyclic GMP-AMP. Little is known about the structure and biochemical function of other proteins of the cGAS-MAB21 subfamily, such as MAB21L1, MAB21L2 and MAB21L3. We have determined the crystal structure of human full-length MAB21L1. Our analysis reveals high structural conservation between MAB21L1 and cGAS but also uncovers important differences. Although monomeric in solution, MAB21L1 forms a highly symmetric double-pentameric oligomer in the crystal, raising the possibility that oligomerization could be a feature of MAB21L1. In the crystal, MAB21L1 is in an inactive conformation requiring a conformational change - similar to cGAS - to develop any nucleotidyltransferase activity. Co-crystallization with NTP identified a putative ligand binding site of MAB21 proteins that corresponds to the DNA binding site of cGAS. Finally, we offer a structure-based explanation for the effects of MAB21L2 mutations in patients with eye malformations. The underlying residues participate in fold-stabilizing interaction networks and mutations destabilize the protein. In summary, we provide a first structural framework for MAB21 proteins
Structural and biochemical characterization of the cell fate determining nucleotidyltransferase fold protein MAB21L1
The exceptionally conserved metazoan MAB21 proteins are implicated in cell fate decisions and share considerable sequence homology with the cyclic GMP-AMP synthase. cGAS is the major innate immune sensor for cytosolic DNA and produces the second messenger 2'-5', 3'-5' cyclic GMP-AMP. Little is known about the structure and biochemical function of other proteins of the cGAS-MAB21 subfamily, such as MAB21L1, MAB21L2 and MAB21L3. We have determined the crystal structure of human full-length MAB21L1. Our analysis reveals high structural conservation between MAB21L1 and cGAS but also uncovers important differences. Although monomeric in solution, MAB21L1 forms a highly symmetric double-pentameric oligomer in the crystal, raising the possibility that oligomerization could be a feature of MAB21L1. In the crystal, MAB21L1 is in an inactive conformation requiring a conformational change - similar to cGAS - to develop any nucleotidyltransferase activity. Co-crystallization with NTP identified a putative ligand binding site of MAB21 proteins that corresponds to the DNA binding site of cGAS. Finally, we offer a structure-based explanation for the effects of MAB21L2 mutations in patients with eye malformations. The underlying residues participate in fold-stabilizing interaction networks and mutations destabilize the protein. In summary, we provide a first structural framework for MAB21 proteins
Convective Concrete: additive manufacturing to facilitate activation of thermal mass
Convective Concrete is about a research-driven design process of an innovative thermal mass concept. The goal is to improve building energy efficiency and comfort levels by addressing some of the shortcomings of conventional building slabs with high thermal storage capacity. Such heavyweight constructions tend to have a slow response time and do not make use of the available thermal mass effectively. Convective Concrete explores new ways of using thermal mass in buildings more intelligently. To accomplish this ondemand charging of thermal mass, a network of ducts and fans is embedded in the concrete wall element. This is done by developing customized formwork elements in combination with advanced concrete mixtures. To achieve an efficient airflow rate, the embedded lost formwork and the concrete itself function like a lung
Protein translocation channel of mitochondrial inner membrane and matrix-exposed import motor communicate via two-domain coupling protein
Abstract The majority of mitochondrial proteins are targeted to mitochondria by N-terminal presequences and use the TIM23 complex for their translocation across the mitochondrial inner membrane. During import, translocation through the channel in the inner membrane is coupled to the ATP-dependent action of an Hsp70-based import motor at the matrix face. How these two processes are coordinated remained unclear. We show here that the two domain structure of Tim44 plays a central role in this process. The N-terminal domain of Tim44 interacts with the components of the import motor, whereas its C-terminal domain interacts with the translocation channel and is in contact with translocating proteins. Our data suggest that the translocation channel and the import motor of the TIM23 complex communicate through rearrangements of the two domains of Tim44 that are stimulated by translocating proteins
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