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tom 58
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nr 2
EN
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.
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tom 72
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nr 08
PL
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.
EN
Current supply chains, in fact we can speak of full ecosystems, the trade in agri-food products is changing in an extremely dynamic way, requiring constant supervision and control of the goods flowing through them. This is an extremely important issue in terms of protecting the health and life of consumers, which, in terms of the concept of corporate social responsibility, puts people at the centre of attention and all activities of enterprises must be geared to their needs. It is therefore very important to check the quality and authenticity of the product's origin in detail, at every stage of its development, so that it can be reacted to as quickly as possible in the event of a risk to consumers' health or life. Maximally short response times as well as safety can be ensured by using Blockchain technology to meet the above requirements. In this article, the authors focused on the use of Blockchain technology in the implementation of logistics processes.
EN
 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.
EN
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.
EN
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.
EN
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
EN
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.
EN
Conformations of globular proteins in the denatured state were studied using a high-resolution lattice model of proteins and Monte Carlo dynamics. The model assumes a united-atom and high-coordination lattice representation of the polypeptide conformational space. The force field of the model mimics the short-range protein-like conformational stiffness, hydrophobic interactions of the side chains and the main-chain hydrogen bonds. Two types of approximations for the short-range interactions were compared: simple statistical potentials and knowledge-based protein-specific potentials derived from the sequence-structure compatibility of short fragments of protein chains. Model proteins in the denatured state are relatively compact, although the majority of the sampled conformations are globally different from the native fold. At the same time short protein fragments are mostly native-like. Thus, the denatured state of the model proteins has several features of the molten globule state observed experimentally. Statistical potentials induce native-like conformational propensities in the denatured state, especially for the fragments located in the core of folded proteins. Knowledge-based protein-specific potentials increase only slightly the level of similarity to the native conformations, in spite of their qualitatively higher specificity in the native structures. For a few cases, where fairly accurate experimental data exist, the simulation results are in semiquantitative agreement with the physical picture revealed by the experiments. This shows that the model studied in this work could be used efficiently in computational studies of protein dynamics in the denatured state, and consequently for studies of protein folding pathways, i.e. not only for the modeling of folded structures, as it was shown in previous studies. The results of the present studies also provide a new insight into the explanation of the Levinthal's paradox.
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