Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 24

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
Protein modeling could be done on various levels of structural details, from simpli­fied lattice or continuous representations, through high resolution reduced models, employing the united atom representation, to all-atom models of the molecular me­chanics. Here I describe a new high resolution reduced model, its force field and ap­plications in the structural proteomics. The model uses a lattice representation with 800 possible orientations of the virtual alpha carbon-alpha carbon bonds. The sam­pling scheme of the conformational space employs the Replica Exchange Monte Carlo method. Knowledge-based potentials of the force field include: generic pro­tein-like conformational biases, statistical potentials for the short-range confor- mational propensities, a model of the main chain hydrogen bonds and context-de­pendent statistical potentials describing the side group interactions. The model is more accurate than the previously designed lattice models and in many applications it is complementary and competitive in respect to the all-atom techniques. The test applications include: the ab initio structure prediction, multitemplate comparative modeling and structure prediction based on sparse experimental data. Especially, the new approach to comparative modeling could be a valuable tool of the structural proteomics. It is shown that the new approach goes beyond the range of applicability of the traditional methods of the protein comparative modeling.
Obecne łańcuchy dostaw, a właściwie możemy mówić o pełnych ekosystemach obrotu produktami rolno-spożywczymi, zmieniają się w sposób bardzo dynamiczny, wymagający stałego nadzoru i kontroli przepływających w nich towarów. Jest to niezmiernie ważki problem ze względu na ochronę zdrowia i życia konsumentów, które w aspekcie idei społecznej odpowiedzialności biznesu stawiają człowieka w centrum uwagi i wszelkie działania przedsiębiorstw muszą być nastawione na jego potrzeby. Z tego też względu bardzo ważna jest szczegółowa kontrola jakości i autentyczności pochodzenia produktu, na każdym etapie jego drogi, służąca do możliwie jak najszybszej reakcji w przypadku zagrożenia zdrowia lub życia konsumentów. Maksymalnie krótki czas reakcji, jak również bezpieczeństwo mogą zostać zapewnione dzięki użyciu technologii Blockchain w aspekcie wyżej opisanych wymogów. W artykule autorzy skupili uwagę na zastosowaniu technologii Blockchain w realizacji procesów logistycznych.
Understanding the interactions of epothilones with β-tubulin is crucial for computer aided rational design of macrocyclic drugs based on epothilones and epothilone derivatives. Despite numerous structure-activity relationship investigations we still lack substantial knowledge about the binding mode of epothilones and their derivatives to β-tubulin. In this work, we reevaluated the electron crystallography structure of epothilone A/β-tubulin complex (PDB entry 1TVK) and proposed an alternative binding mode of epothilone A to β-tubulin that explains more experimental facts.
 1,25-dihydroxyvitamin D3 has quite significant anticancer properties, but its strong calcemic effect in principle excludes it as a potential anticancer drug. Currently, a lot of effort is being devoted to develop potent anticancer analogs of 1,25-dihydroxyvitamin D3 that would not induce hypercalcemia during therapy. In this work, the free binding energy of the VDR receptor with 1,25-dihydroxyvitamin D3 and its three potent analogs (EB 1089, KH 1060 and RO 25-9022) is calculated and compared with each other. With this approach, we could estimate the relative binding affinity of the most potent analog, RO 25-9022, and also revealed a quite distinct mechanism of its interaction with VDR.
Prediction of protein secondary structure by an enhanced neural networ
Ustawianie zmieniające się potrzeby rynkowe oraz koncentracja całego łańcucha dostaw na poziomie obsługi klienta wymuszają zarówno w świecie biznesowym, jak i naukowym poszukiwanie nowoczesnych rozwiązań usprawniających procesy logistyczne. Obecnie można zauważyć liczne innowacyjne rozwiązania kierujące łańcuchy dostaw na drogę cyfryzacji. Instytut Logistyki i Magazynowania oraz Wyższa Szkoła Logistyki od 2017 roku prowadzą intensywne prace badawcze zarówno w sferze naukowej, jak i możliwości zastosowania poszczególnych rozwiązań w praktyce biznesowej. W artykule przedstawiono koncepcję opracowaną w celu oceny efektywności integracji komunikacyjnej zautomatyzowanych procesów produkcyjnych jako jednego z kluczowych ogniw inteligentnego łańcucha dostaw. Wynikiem opracowanej koncepcji jest udział w projekcie badawczym L4MS (Smart logistics for manufacturing), a po zakończeniu prac projektowych możliwość weryfikacji efektywności zastosowania inteligentnych rozwiązań w praktyce gospodarczej.
A high coordination lattice discretization of protein conformational space is described. The model allows discrete representation of polypeptide chains of globular proteins and small macromolecular assemblies with an accuracy comparable to the accuracy of crystallographic structures. Knowledge based force Held, that consists of sequence specific short range interactions, coopera­tive model of hydrogen bond network and tertiary one body, two body and multibody interactions, is outlined and discussed. A model of stochastic dy­namics for these protein models is also described. The proposed method enables moderate resolution tertiary structure prediction of simple and small globular proteins. Its applicability in structure prediction increases significantly when evolutionary information is exploited or/and when sparse experimental data are available. The model responds correctly to sequence mutations and could be used at early stages of a computer aided protein design and protein redesign. Computational speed, associated with the discrete structure of the model, enables studies of the long time dynamics of polypeptides and proteins and quite detailed theoretical studies of thermodynamics of nontrivial protein models.
A new approach to comparative modeling of proteins, TRACER, is described and benchmarked against classical modeling procedures. The new method unifies true three-dimensional threading with coarse-grained sampling of query protein conformational space. The initial sequence alignment of a query protein with a template is not required, although a template needs to be somehow identified. The template is used as a multi-featured fuzzy three-dimensional scaffold. The conformational search for the query protein is guided by intrinsic force field of the coarse-grained modeling engine CABS and by compatibility with the template scaffold. During Replica Exchange Monte Carlo simulations the model chain representing the query protein finds the best possible structural alignment with the template chain, that also optimizes the intra-protein interactions as approximated by the knowledge based force field of CABS. The benchmark done for a representative set of query/template pairs of various degrees of sequence similarity showed that the new method allows meaningful comparative modeling also for the region of marginal, or non-existing, sequence similarity. Thus, the new approach significantly extends the applicability of comparative modeling.
À complex, cascaded neural network designed to predict the secon­dary structure of globular proteins has been developed. Information about the local buried-unburied pattern and the average tendency of the particular types of amino acids to be buried inside the globule were used. Nonspecific information about long distance contact maps was also employed. These modifications result in a noticeable improvement (3 - 9%) of prediction accuracy. The best result for the average success ratio for the testing set of nonhomologous proteins was 68.3% (with corresponding Matthews' coefficients, C
A high resolution reduced model of proteins is used in Monte Carlo dynamics studies of the folding mechanism of a small globular protein, the B1 immunoglobulin-binding domain of streptococcal protein G. It is shown that in order to reproduce the physics of the folding transition, the united atom based model requires a set of knowledge-based potentials mimicking the short-range conformational propensities and protein-like chain stiffness, a model of directional and cooperative hydrogen bonds, and properly designed knowledge-based potentials of the long-range interactions between the side groups. The folding of the model protein is cooperative and very fast. In a single trajectory, a number of folding/unfolding cycles were observed. Typically, the folding process is initiated by assembly of a native-like structure of the C-terminal hairpin. In the next stage the rest of the four-ribbon β-sheet folds. The slowest step of this pathway is the assembly of the central helix on the scaffold of the β-sheet.
A high coordination lattice model was used to represent the protein chain. Lattice points correspond to amino-acid side groups. A complicated force field was designed in order to reproduce a protein-like behavior of the chain. Long-distance tertiary re­straints were also introduced into the model. The Replica Exchange Monte Carlo method was applied to find the lowest energy states of the folded chain and to solve the problem of multiple minima. In this method, a set of replicas of the model chain was simulated independently in different temperatures with the exchanges of replicas allowed. The model chains, which consisted of up to 100 residues, were folded to structures whose root-mean-square deviation (RMSD) from their native state was between 2.5 and 5 A. Introduction of restrain based on the positions of the backbone hydrogen at­oms led to an improvement in the number of successful simulation runs. A small im­provement (about 0.5 A) was also achieved in the RMSD of the folds. The proposed method can be used for the refinement of structures determined experimentally from NMR data.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.