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Protein S is a vitamin K-dependent plasma protein. It functions as a cofactor to activated protein C in the inactivation of factors Va and VIIIa by limited proteolysis. Protein S is very sensitive to proteolysis by thrombin which reduces its calcium ion binding and leads to a loss of its cofactor activity. We have now determined the sequence of the 100 amino-terminal amino acid residues and locali
Proteins carrying genetically attached polyhistidine tails have been purified using affinity precipitation with metal chelates. DNA fragments encoding four or five histidine residues have been genetically fused to the oligomeric enzymes lactate dehydrogenase (Bacillus stearothermophilus), beta-glucoronidase (Escherichia coli), and galactose dehydrogenase (Pseudomonas fluorescens) as well as to the
Low-energy-electron-diffraction (LEED), scanning-tunneling-microscopy (STM), and photoelectron-spectroscopy measurements have been performed on the ordered submonolayer surface reconstructions of Yb on Si(111). Two of these reconstructions, namely, 3×1 and 2×1, have been studied in detail. STM and LEED revealed that what was considered to be the 3×1 reconstruction is actually a 3×2 reconstruction.
M1 aminopeptidases comprise a large family of biologically important zinc enzymes. We show that peptide turnover by the M1 prototype, leukotriene A4 hydrolase/aminopeptidase, involves a shift in substrate position associated with exchange of zinc coordinating groups, while maintaining the overall coordination geometry. The transition state is stabilized by residues conserved among M1 members and i
Nitric oxide (NO) can modulate both tumor growth and antitumor immune responses. In order to elucidate the mechanism of curative therapeutic immunization with IFNgamma-producing glioma cells, we examined the expression of inducible nitric oxide synthase (iNOS) in tissue sections from immunized animals. There was a significantly enhanced iNOS expression both intratumorally and at the immunization s
Leukotriene ( LT) A(4) hydrolase is a bifunctional zinc metalloenzyme, which converts LTA(4) into the neutrophil chemoattractant LTB4 and also exhibits an anion-dependent aminopeptidase activity. In the x-ray crystal structure of LTA(4) hydrolase, Arg(563) and Lys(565) are found at the entrance of the active center. Here we report that replacement of Arg(563), but not Lys(565), leads to complete a
Nature provides science and society with a virtually unlimited supply of structurally diverse and biologically active molecules; the natural products. While some are directly useful in commercial applications, others are valuable for studying and understanding biological phenomena at the molecular level. An example is the signaling of nerve cells, which has been explored in considerable detail usi
The maximum light use efficiency (LUE = gross primary production (GPP)/absorbed photosynthetic photon flux density (aPPFD)) of plant canopies has been reported to vary spatially and some of this variation has previously been attributed to plant species differences. The canopy nitrogen concentration [N] can potentially explain some of this spatial variation. However, the current paradigm of the N-e
Prospective cohort studies about cutaneous melanoma (CM) risk are still few. Host factor- and UVR exposure data were collected prospectively by questionnaire in this population-based cohort study including 40000 Swedish born women, aged 25-64 years at enrolment (1990). Risk for CM (Cox regression and Stepwise Cox regression [SCR], hazard ratios [HRs] with 95 % Confidence Intervals [CI]) in relatio
Arctic tundra vegetation composition is expected to undergo rapid changes during the coming decades because of changes in climate. Higher air temperatures generally favor growth of deciduous shrubs, often at the cost of moss growth. Mosses are considered to be very important to critical tundra ecosystem processes involved in water and energy exchange, but very little empirical data are available.
Abstract in UndeterminedSoil microbes constitute an important control on nitrogen (N) turnover and retention in arctic ecosystems where N availability is the main constraint on primary production. Ectomycorrhizal (ECM) symbioses may facilitate plant competition for the specific N pools available in various arctic ecosystems. We report here our study on the N uptake patterns of coexisting plants an
