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C-Nanostructures Cluster Models in Organic Solvents： Fullerenes, Tubes, Buds and Graphenes

Journal of Chemistry and Chemical Engineering 2013年第11期7卷 1026-1035页

作者： francisco torrens Gloria Castellano University Institute for Molecular Science University of Valencia Valencia 46071 Spain Faculty of Veterinary and Experimental Sciences Valencia Catholic University Saint Vincent Martyr Valencia 46001 Spain

The existence of nanographene in cluster form is discussed in organic solvents. Theories are developed based on the columnlet, bundlet and droplet models describing the size-distribution functions. Phenomena present a unified explanation in the columnlet model in which free energy of Cgraphene involved in cluster is combined from a volume part proportional to the number of molecules n in cluster and a constant. The columnlet model enables describing distribution function of Cgraphene clusters by size. From purely geometrical considerations the columnlet （Cgraphene）, bundlet （single-wall carbon nanotube）, CNT （carbon nanotube）, SWNT （single-wall C-nanotube）, and carbon nanobud, CNB （carbon nanobud）） and droplet （fullerene） models predict dissimilar behaviours. The interaction-energy parameters of Cgraphene are taken from C60. An CNB behaviour or further is expected. The decay of solubility with rising temperature is smaller for Cgraphene than for SWNT and CNB and, furthermore, than for C60, in agreement with lesser numbers of units in Cgraphene clusters. The discrepancy between the experimental data of the heat of solution of fullerenes, CNTs, CNBs and graphenes is ascribed to the sharp concentration dependence of the heat of solution. The diffusion coefficient drops with temperature result greater for Cgraphene than CNB and SWNT than C60 corresponding to lesser number of units in clusters. The aggregates near （C60）13, SWNT/CNB7 and （Cgraphene）3 could be representative of the droplet, bundlet and columnlet models.

关键词： Nanostructure graphene solubility columnlet cluster model bundlet cluster model droplet cluster model nanobud.

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Binding of Mono, Bi and Tridomain Proteins to Zwitterionic and Anionic Vesicles： Asymmetric Location of Anionic Phospholipids in Mixed Zwitterionic/Anionic Vesicles and Cooperative Binding

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Journal of Life Sciences 2011年第3期5卷 167-181页

作者： francisco torrens Gloria Castellano Institute for Molecular Science University of Valencia Valencia E-46071 Spain Energesis Chair of Interdisciplinary Technology Saint Vincent Martyr Catholic University of Valencia Valencia E-46003 Spain

Lysozyme, myoglobin and BSA were used as models of globular proteins covering a wide range of pl. The purpose is to extend the studies to anionic lipid bilayers. Electrostatics is studied in cationic protein adsorption to zwitterionic PC and anionic mixed PC/PG SUVs. Protein adsorption is investigated in SUVs along with changes of fluorescence emission spectra. Partition coefficients and cooperativity parameters are calculated. At pl binding obtains maximum while at lower or higher pHs binding decreases. In Gouy-Chapman formalism activity coefficient goes with square charge, which deviations indicate asymmetric location of anionic phospholipid in the inner leaflet, in mixed SUVs for lysozyme- and myoglobin-PC/PG systems, in agreement with experiments and molecular dynamics simulations. Vesicles bind myoglobin anti-cooperatively while lysozyme-BSA cooperativitivey. A model is proposed for both, which composes two protein sub-layers with different structures and properties. Hill coefficient reflects subunit cooperativity of bi and tridomain proteins.

关键词： Protein-lipid interaction sigmoid adsorption isotherm transbilayer asymmetry anionic phospholipid asymmetric location cooperative binding hill plot.

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Estimation of Partition Coefficients of Fe-S Protein Models： Se Substitutions in Fe4S4Cysn

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Journal of Chemistry and Chemical Engineering 2012年第10期6卷 867-877页

作者： francisco torrens Gloria Castellano Institute for Molecular Science University of Valencia Valencia 46071 Spain Faculty of Veterinary and Experimental Sciences Catholic University of Valencia Saint Vincent-Martyr Valencia 46001 Spain

The SCAP method allows a semiquantitative estimation of the partitioning of many solutes between numerous pairs of solvents. The organic solvent-water partition coefficients P are calculated. For FeaS4Cysn, the organic solvent-water partition coefficients for l-octanol Po, cyclohexane Pch and chloroform Pcf decay 4.46, 6.25 and 4.60 log units per Cys, respectively. The Po is of the same order of magnitude as CDHI （conformationally dependent hydrophobic index） calculations and Pch-cf as computations performed with a method by Leo and Hansch. The logPo-ch-cf mean relative errors are 17%, 25% and-17%, which represent mean and unsigned relative errors of -3% and 20%. On varying the number of Cys, the structures show hydrophobic moments indicative of amphipathic compounds. For Se substitutions in Fe4SeaCys,, Po-ch-cf drop 4.52, 6.30 and 4.66 exponents per Cys. With the reference calculations, Po-ch-cf decay 4.03, 4.80 and 5.76 exponents per Cys. For FeaS4 mSemCys4, the calculated similar partition coefficients and hydrophobic moments, and lower distance in dendrogram suggest a role of Fe-Se clusters in physiological processes. The analysis is extended to lysozyme and its secondary structures.

关键词： Solvation parameter model partition coefficient hydrophobic moment iron-sulphur protein mixed-valence non-integeroxidation number.

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Virtual screening of flavonoids from Jatropha gossypiifolia *** potential drugs for diabetic complications

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Traditional Medicine Research 2022年第2期7卷 34-42页

作者： Yudith Cañizares-Carmenate Roberto Díaz-Amador Mirtha Mayra Gonzalez-Bedia Tan Tran Quang Nhat francisco torrens Juan Alberto Castillo-Garit Unit of Computer-Aided Molecular“Biosilico”Discovery and Bioinformatic Research Departamento de FarmaciaFacultad de Química-FarmaciaUniversidad Central“Marta Abreu”de Las VillasSanta Clara 54830Villa ClaraCuba Departamento de Ciencias de la Computación Facultad de MatemáticaFísica y ComputaciónUniversidad CelaraCuntral“Marta Abreu”de Las VillasSanta Clara 54830Villa ClaraCuba Institut Universitari de Ciència Molecular Universitat de ValènciaEdifici d’Instituts de PaternaP.O.Box 22085ValènciaSpain. Unidad de Toxicología Experimental Universidad de Ciencias Médicas de Villa ClaraSanta Clara 50200Villa ClaraCuba.

Background:Diabetes mellitus is a chronic metabolic disease that is a risk factor for epidemic *** hyperglycemic conditions,the enzyme aldose reductase catalyzes the formation of sorbitol in the metabolism of glucose via polyols,leading to the development of diabetic ***,inhibitors of this enzyme are therapeutic targets for the prophylaxis and treatment of these ***:In this study,a generalized linear regression model was developed to analyze flavonoids-obtained from a database-that have been tested as inhibitors of aldose *** this sense,the molecular descriptors implemented in DRAGON and MATLAB software were used to determine the correlation between the chemical structure of the inhibitors and their pharmacological *** model was validated according to the Organisation for Economic Co-operation and Development Standards and subsequently used for the virtual screening of the flavonoids identified in Jatropha gossypiifolia ***:The proposed model showed a good fit for its statistical parameters(R2=0.95).In addition,it showed good predictive power(R2 ext=0.94)and robustness(Q2 LOO=0.92).The experimental chemical space wherein the predictions were reliable(domain of application)was also ***,the model was used to identify 10 flavonoids from Jatropha gossypiifolia *** candidates for natural *** with a low probability of oral absorption were identified,among which the elagic acid biflavonoid showed the greatest promise(pIC50 predicted=9.75).Conclusion:The Jatropha gossypiifolia *** harbors flavonoids with high potential as inhibitors of the aldose reductase enzyme,in which the biflavonoid ellagic acid was shown to be the most promising inhibitor of the aldose reductase enzyme,suggesting its possible use in the treatment of the late complications of diabetes mellitus.

关键词： Jatropha gossypiifolia L. aldose reductase generalized linear regression model diabetic complications

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A Tool for Interrogation of Macromolecular Structure

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材料科学与工程：中英文B版 2014年第2期4卷 55-63页

作者： francisco torrens Gloria Castellano University Institute for Molecular Science University of Valencia Building of Institutes of Paterna P. O. Box 22085 Valencia46071 Spain Faculty of Veterinary and Experimental Sciences Valencia Catholic University Saint Vincent Martyr Guillem de Castro-94Valencia 46001 Spain

Our program BABELPDB allows browsing and interrogating the native and derived structural features of biomacromolecules using data obtained from the Protein Data Bank (PDB). Major features of BABELPDB are: (1) convert from PDB to other formats, (2) add or remove H-atoms, (3) strip the crystallization water molecules and (4) separate the ?-carbons (C ? ). The co-ordinates obtained with BABELPDB permit characterizing the presence of H-bonds. The algorithm for detecting H-bonds is implemented in our program TOPO for the theoretical simulation of the molecular shape. An example is given to illustrate the capabilities of the software: the calculation of the fractal dimension of the lysozyme molecule with (1.908) and without (1.920) H-atoms. The figures compare well with reference calculations performed with our version of program GEPOL and results from Pfeifer et al. For proteins, C ? -skeleton extracted with BABELPDB allows drawing the ribbon image, which determines their secondary structure.

关键词：大分子结构蛋白质数据库工具生物大分子结构特征分子形状 TOPO 分形维数

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