An NMR investigation of the structure-function characteristics of the Pseudomonas aeruginosa dimethylarginine dimethylaminohydrolase.

The enzyme dimethylarginine dimethylaminohydrolase (DDAH) is responsible for the metabolism of free asymmetric methylarginine residues (AMAs) to citrulline and mono- or di-methylamines. In mammals, the asymmetric methylarginines NN11-dimethylarginine (ADMA) and Nn-methylarginine (L-NMMA) are endogenous inhibitors of all nitric oxide synthase (NOS) isoforms. By controlling local levels of AMAs, DDAH activity is implicated in the regulation of nitric oxide (NO) production, which gives rise to interest in the therapeutic potential of this enzyme. This work describes the application of NMR methodology to study the backbone dynamics of PaDDAH and interactions with ligands and inhibitors, as this protein provides an attractive template to further investigate the structure-function characteristics of DDAH isoforms and p/a-propeller enzymes in general. To counter the relatively large size of the enzyme for NMR studies and the difficulties to obtain unambiguous resonance assignments for the amide backbone resonances of the 58 kD homodimer, a monomeric and fully active variant of PaDDAH was engineered through rational design of site-directed mutation of two interfacial residues. The exclusively monomeric R40E- R98H double mutant protein proved more tractable by heteronuclear NMR than the wild-type homodimer. 15N backbone relaxation studies of the mutant protein, analysed in the model-free formalism, revealed that the loop that closes down on the ligand in the active site displays low values of the generalised N-H bond order parameter (S2) consistent with a high degree of mobility on the pico- to nanosecond timescale. The interaction of PaDDAH with a variety of small molecule ligands was followed by heteronuclear NMR experiments. A general observation is that ligands that act as inhibitors of the enzyme in vitro give rise to specific broadening of a subset of N-H cross peaks, including those of residues around the active site and in the loop that closes the ligand binding pocket. The results are interpreted to imply that in the bound state the dynamic profile of the backbone of the PaDDAH enzyme is altered, probably with ordering of the loop but retaining a component of conformational exchange that gives rise to residual line broadening, even in the saturated state. A similar result is obtained with a ligand covalently bound to Cys249 of the catalytic triad

Building blocks and structural patterns in silicon clusters : global and local optimizations employing empirical potentials, density functionals, and ab-initio calculations

Sin clusters in the size range n=4-35 have been investigated, using a combination of global structure optimization methods with DFT and ab-initio calculations. One of the central aims is to provide explanations for the structural transition from prolate to spherical outer shapes at about n=25, as observed in ion mobility measurements. First, several empirical potentials for silicon and a newly generated variant of one of them were better adapted to small silicon clusters, by global optimization of their parameters. The best resulting empirical potentials were then employed in global cluster structure optimizations. The most promising structures from this stage were relaxed further at the DFT level with a hybrid B3LYP functional. For the resulting structures, single point energies have been calculated at the LMP2 level with cc-pVTZ basis set. Results obtained at the DFT level strongly support the shape transition form prolate to spherical structures beginning with Si26. In contrast, at the LMP2 level, the dominance of spherical structures after the transition region could not be confirmed

Effects of inbreeding on human quantitative traits and complex common diseases of late-onset

Studying the effects of inbreeding in human populations could provide insights into the genetic architecture of medically relevant quantitative traits and common complex diseases of late onset. In a historic example of 2,761 examinees from isolated village populations of the islands of Brae, Hvar and Korcula, Croatia, collected through field work undertaken in the 1970's and 1980's, individual inbreeding coefficients were computed based on genealogical records. Inbreeding showed a strong positive effect on blood pressure and negative on cortical index. The 14 villages were revisited in 2000 to assess the prevalence of learning disability and of common complex diseases of late onset. A cohort study and an ecological study, after appropriate standardization, both showed that inbreeding increased the prevalence of coronary heart disease, stroke, psychiatric disorders, cancer, gout, asthma, glaucoma and peptic ulcer, but not type II diabetes. A strong effect on the prevalence of learning disability was also noted in 10 villages. In a followup study on 1,001 examinees from 10 other villages sampled on neighbouring islands in 2002, positive effects of outbreeding on fitness, height, blood pressure, cholesterol and triglyceride values were detected. The possible explanations for the observed effects include: (i) The joint effect of inbreeding depression on all polygenic quantitative phenotypes that confer risk for lateonset diseases is predicted to be multiplicative rather than additive, (ii) The "genetic load" of rare "Mendelian" variants with large deleterious effects in post-reproductive adults is unknown, but could be much greater than expected as these variants were invisible to selection through human history, (iii) Deleterious effects resulting from autozygosity in hundreds of affected rare recessive variants of small effect under common disease/rare variant (CD/RV) hypothesis could result in epistatic effects that could jointly impair the capacity to compensate against environmental risks, (iv) Heterozygote advantage in loci under balancing selection could be reduced by inbreeding. Consanguinity is common in many populations and the possible effects of inbreeding depression on disease burden and reduced life expectancy should be further investigated

Novi profil gradskih luka u razvoju nautičkog turizma

Maritime ports are an integral part of the large towns, their most attractive, and at the same time, their most profitable area. The development of ports in Croatia and in the Mediterranean has proceeded alongside the development of maritime towns. Their age parallels the age of the towns. Throughout history, town ports have changed their economic role and profile adapting to the needs of the market and towns. The development of nautical tourism has placed great pressure on the old ports changing their existing profile. Over the centuries, town ports of large and medium-size towns have performed the function of maritime traffic, transportation of persons and cargo, and trade. For nautical tourism to achieve good development results and a consistently high development rate, it is necessary to change the classical profile of town ports by transforming them from maritime ports into ports for nautical tourism. What types of changes are involved? What do these changes bring? The answers to these questions and others shall be given in this article.Pomorske luke dio su velikih gradova i njihova najatraktivnija i najvrjednija područja. Razvoj luka u Hrvatskoj i na Mediteranu išao je u korak s razvojem gradova na obali. Njihova starost jednaka je starosti grada. Tijekom povijesti, gradske su luke mijenjale svoju gospodarsku ulogu i profil, prilagođavajući se potrebama tržišta i grada. Razvoj nautičkog turizma izvršio je na stare luke veliki pritisak, u smislu promjene njihovog postojećeg profila. Gradske luke velikih i srednje velikih gradova vjekovima su u funkciji pomorskog prometa, prijevoza ljudi i tereta i trgovine. Dobri razvojni rezultat nautičkog turizma i kontinuirano visoke razvojne stope, zahtijevaju promjenu klasičnog profila gradskih luka na način da se luke za pomorski promet transformiraju u luke nautičkog turizma. O kakvim se promjenama radi? Što donose te promjene? Na ova i druga pitanja nastoji se odgovoriti u ovom tekstu

Novi profil gradskih luka u razvoju nautičkog turizma

Maritime ports are an integral part of the large towns, their most attractive, and at the same time, their most profitable area. The development of ports in Croatia and in the Mediterranean has proceeded alongside the development of maritime towns. Their age parallels the age of the towns. Throughout history, town ports have changed their economic role and profile adapting to the needs of the market and towns. The development of nautical tourism has placed great pressure on the old ports changing their existing profile. Over the centuries, town ports of large and medium-size towns have performed the function of maritime traffic, transportation of persons and cargo, and trade. For nautical tourism to achieve good development results and a consistently high development rate, it is necessary to change the classical profile of town ports by transforming them from maritime ports into ports for nautical tourism. What types of changes are involved? What do these changes bring? The answers to these questions and others shall be given in this article.Pomorske luke dio su velikih gradova i njihova najatraktivnija i najvrjednija područja. Razvoj luka u Hrvatskoj i na Mediteranu išao je u korak s razvojem gradova na obali. Njihova starost jednaka je starosti grada. Tijekom povijesti, gradske su luke mijenjale svoju gospodarsku ulogu i profil, prilagođavajući se potrebama tržišta i grada. Razvoj nautičkog turizma izvršio je na stare luke veliki pritisak, u smislu promjene njihovog postojećeg profila. Gradske luke velikih i srednje velikih gradova vjekovima su u funkciji pomorskog prometa, prijevoza ljudi i tereta i trgovine. Dobri razvojni rezultat nautičkog turizma i kontinuirano visoke razvojne stope, zahtijevaju promjenu klasičnog profila gradskih luka na način da se luke za pomorski promet transformiraju u luke nautičkog turizma. O kakvim se promjenama radi? Što donose te promjene? Na ova i druga pitanja nastoji se odgovoriti u ovom tekstu

6th International Probabilistic Workshop - 32. Darmstädter Massivbauseminar: 26-27 November 2008 ; Darmstadt, Germany 2008 ; Technische Universität Darmstadt

These are the proceedings of the 6th International Probabilistic Workshop, formerly known as Dresden Probabilistic Symposium or International Probabilistic Symposium. The workshop was held twice in Dresden, then it moved to Vienna, Berlin, Ghent and finally to Darmstadt in 2008. All of the conference cities feature some specialities. However, Darmstadt features a very special property: The element number 110 was named Darmstadtium after Darmstadt: There are only very few cities worldwide after which a chemical element is named. The high element number 110 of Darmstadtium indicates, that much research is still required and carried out. This is also true for the issue of probabilistic safety concepts in engineering. Although the history of probabilistic safety concepts can be traced back nearly 90 years, for the practical applications a long way to go still remains. This is not a disadvantage. Just as research chemists strive to discover new element properties, with the application of new probabilistic techniques we may advance the properties of structures substantially. (Auszug aus Vorwort

50th Rocky Mountain Conference on Analytical Chemistry

Final program, abstracts, and information about the 50th annual meeting of the Rocky Mountain Conference on Analytical Chemistry, co-endorsed by the Colorado Section of the American Chemical Society and the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Breckenridge, Colorado, July 27-31, 2008