@article {299, title = {2-Methylene analogs of 1alpha-hydroxy-19-norvitamin D3: synthesis, biological activities and docking to the ligand binding domain of the rat vitamin D receptor}, journal = {The Journal of Steroid Biochemistry and Molecular Biology}, volume = {89-90}, year = {2004}, month = {2004 May}, pages = {13-7}, abstract = {In continuing efforts towards the synthesis of biologically active vitamin D compounds of potential therapeutic value, new 2-methylene-1alpha-hydroxy-19-norvitamin D(3) analogs 3 and 4 with modified alkyl side chains have been synthesized. The key synthetic step involved Lythgoe-type Wittig-Horner coupling of Windaus-Grundmann type ketones 9, possessing different 17beta-alkyl substituents, with the phosphine oxide 10 prepared from (-)-quinic acid. The prepared vitamins 3 and 4 were ca. eight times less potent than 1alpha,25-dihydroxyvitamin D(3) (1alpha,25-(OH)(2)D(3)) (1) in binding to the rat intestinal vitamin D receptor (VDR). In comparison with the hormone 1 they exhibited slightly lower cellular HL-60 differentiation activity. When tested in vivo; the analog 3 was characterized by very high bone calcium mobilizing potency and intestinal calcium transport activity. Unexpectedly, the 25-methyl compound 4 showed marked calcemic activity in both assays. Computational docking of the vitamin 3 into the binding pocket of the rat vitamin D receptor is also reported.}, keywords = {Animals, Binding Sites, Calcitriol, Female, HL-60 Cells, Humans, Hydrocarbons, Ligands, Methane, Mice, Models, Molecular, Rats, Receptors, Calcitriol}, issn = {0960-0760}, doi = {10.1016/j.jsbmb.2004.03.103}, author = {Pawel Grzywacz and Lori A. Plum and Wanda Sicinska and Rafal R. Sicinski and Jean M. Prahl and Hector F. DeLuca} } @article {Rey1992, title = {Effect of double bonds on the dynamics of hydrocarbon chains}, journal = {Journal of Chemical Physics}, volume = {97}, year = {1992}, pages = {1240{\textendash}1249}, abstract = {Brownian dynamics simulations of isolated 18-carbon chains have been performed, both for saturated and unsaturated hydrocarbons. The effect of one or several (nonconjugated) double bonds on the properties of the chains is discussed in terms of both equilibrium and dynamic properties. The introduction of a cis double bond increases the relaxation rates of the unsaturated chain with respect to the saturated alkane. On the other hand, coupling effects in the torsional transitions around a trans double bond make the dynamics of this unsaturated chain very similar to the saturated one. Based on these results, the parameters and moves of a dynamic Monte Carlo algorithm are tuned to reproduce the observed behavior, providing an efficient method for the study of more complicated systems.}, keywords = {Algorithms, Brownian Movement, Chains, Coupling, Double Bonds, dynamics, equilibrium, Hydrocarbons, Monte Carlo Method, Relaxation, Saturation, simulation, Torsion}, doi = {10.1063/1.463250}, url = {http://smartech.gatech.edu/handle/1853/26936}, author = {Antonio Rey and Andrzej Koli{\'n}ski and Jeffrey Skolnick and Yehudi K. Levine} } @article {Levine1991, title = {Monte Carlo dynamics study of motions in cis-unsaturated hydrocarbon chains}, journal = {The Journal of Chemical Physics}, volume = {95}, year = {1991}, pages = {3826{\textendash}3834}, abstract = {A Monte Carlo dynamics study of the motions of hydrocarbon chains containing cis double bonds is presented. The simulations utilize the high-coordination {2 1 0} lattice for the simultaneous representation of the tetrahedrally bonded carbon atoms and the planar unsaturated segment. Results on single chains undergoing free motion in space and tethered to an impenetrable planar interface are reported. The introduction of a cis double bond into a hydrocarbon chain induces a slowdown in the dynamics. The simulations show this to be a universal result independent of the representation of the chain on the lattice. In contrast, polyunsaturated chains are found to be more mobile than saturated ones.}, keywords = {Bilayers, Chains, Chemical Bonds, Hydrocarbons, Hydrogen Bonds, Lipids, Molecular Motion, Monte Carlo Method, Temperature Effects}, doi = {10.1063/1.460782}, url = {http://smartech.gatech.edu/handle/1853/26899}, author = {Yehudi K. Levine and Jeffrey Skolnick and Andrzej Koli{\'n}ski} }