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Molecular Field (molecular + field)

Distribution by Scientific Domains
Chemistry83%

Terms modified by Molecular Field

  • molecular field analysis
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    Selected Abstracts

    A combined molecular modeling study on gelatinases and their potent inhibitors

    JOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 1 2010
    Lili Xi
    Abstract Zinc-dependent matrix metalloproteinase (MMP) family is considered to be an attractive target because of its important role in many physiological and pathological processes. In the present work, a molecular modeling study combining protein-, ligand- and complex-based computational methods was performed to analyze a new series of ,- N -biaryl ether sulfonamide hydroxamates as potent inhibitors of gelatinase A (MMP-2) and gelatinase B (MMP-9). Firstly, the similarities and differences between the binding sites of MMP-2 and MMP-9 were analyzed through sequence alignment and structural superimposition. Secondly, in order to extract structural features influencing the activities of these inhibitors, quantitative structure-activity relationship (QSAR) models using genetic algorithm-multiple linear regression (GA-MLR), comparative molecular field (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) were developed. The proposed QSAR models could give good predictive ability for the studied inhibitors. Thirdly, docking study was employed to further explore the binding mode between the ligand and protein. The results from all the above analyses could provide the information about the similarities and differences of the binding mode between the MMP-2, MMP-9 and their potent inhibitors. The obtained results can provide very useful information for the design of new potential inhibitors. © 2009 Wiley Periodicals, Inc. J Comput Chem 2010 [source]

    Origin of the X-ray magnetic circular dichroism at the L -edges of the rare-earths in RxR1,x,Al2 systems

    JOURNAL OF SYNCHROTRON RADIATION, Issue 3 2009
    Jesús Chaboy
    An X-ray magnetic circular dichroism (XMCD) study performed at the rare-earth L2,3 -edges in the RxR1,x,Al2 compounds is presented. It is shown that both R and R, atoms contribute to the XMCD recorded at the L -edges of the selected rare-earth, either R or R,. The amplitude of the XMCD signal is not directly correlated to the magnetization or to the value of the individual (R, R,) magnetic moments, but it is related to the molecular field acting on the rare-earth tuned in the photoabsorption process. This result closes a longstanding study of the origin of the XMCD at the L -edge of the rare-earths in multi-component systems, allowing a full understanding of the exact nature of these signals. [source]

    Magnetisation dynamics of Fe nanoclusters exchange-coupled to magnetic substrates

    PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 15 2004
    C. Binns
    Abstract Synchrotron radiation was used to study exposed Fe nanoclusters with controlled sizes in the size range 140,270 atoms (1.5,1.8 nm) deposited in situ from a gas aggregation source on to magnetic vitrovac amorphous ribbons. Magnetic linear dichroism in the angular distribution (MLDAD) of the Fe 3p core level photoemission was used to show that the clusters are exchange-coupled to the substrate with an interface molecular field of about 20 T. The switching dynamics was studied on the nanosecond timescale by time-resolved spin-polarised photoemission. At low coverages, below the percolation threshold, when the film consists of separated islands the switching dynamics of the cluster islands is identical to the clean substrate. At around the percolation threshold, however, the data indicates that the magnetic reversal propagates faster in the cluster film than in the substrate. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    Conceptual DFT properties-based 3D QSAR: Analysis of inhibitors of the nicotine metabolizing CYP2A6 enzyme

    JOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 12 2009
    Sofie Van Damme
    Abstract Structure-activity relationships of 46 P450 2A6 inhibitors were analyzed using the 3D-QSAR methodology. The analysis was carried out to confront the use of traditional steric and electrostatic fields with that of a number of fields reflecting conceptual DFT properties: electron density, HOMO, LUMO, and Fukui f, function as 3D fields. The most predictive models were obtained by combining the information of the electron density with the Fukui f, function (r2 = 0.82, q2 = 0.72), yielding a statistically significant and predictive model. The generated model was able to predict the inhibition potencies of an external test set of five chemicals. The result of the analysis indicates that conceptual DFT-based molecular fields can be useful as 3D QSAR molecular interaction fields. © 2008 Wiley Periodicals, Inc. J Comput Chem 2009 [source]

    A 3-D QSAR Study of Catechol- O -Methyltransferase Inhibitors Using CoMFA and CoMSIA

    MOLECULAR INFORMATICS, Issue 10 2008
    Chunzhi Ai
    Abstract Inhibitors of Catechol- O -Methyltransferase (COMT) play an important role in the treatment of Parkinson's Disease (PD). A new Three-Dimensional Quantitative Structure,Activity Relationship (3-D QSAR) analysis was performed on 36 previously reported COMT inhibitors employing Comparative Molecular Field Analysis (CoMFA) and Comparative Molecular Similarity Indices Analysis (CoMSIA) methodologies to correlate the molecular fields and percent inhibition values and three predictive models were derived. The CoMFA and CoMSIA models with steric and electrostatic field yielded cross-validated rs of 0.585 and 0.528, respectively whereas the conventional rs were 0.979 and 0.891, respectively. The CoMSIA model with hydrophobic field exhibited a r of 0.544 and a r of 0.930. The individual inspection of 3-D contours generated from these models helps in understanding the possible region for structural modification of molecules to improve the inhibitory bioactivity. These 3-D QSAR models are also useful for designing and predicting novel COMT inhibitors. [source]

    Steering Two-Dimensional Molecular Growth via Dipolar Interaction

    CHEMPHYSCHEM, Issue 12 2009
    Stefan Kuck
    Molecular networks: Chiral and metallized Salen molecules on a Cu(111) are investigated using local probe techniques (see figure). Whereas for the parent Co-Salen molecule no self-assembly is observed, in the metal,organic complexes the growth of large and regular molecular networks is achieved through a target-oriented synthetic design of the local electrostatic dipolar molecular fields. [source]