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2002

Biochemistry, Biophysics, and Structural Biology

Articles 1 - 4 of 4

Full-Text Articles in Life Sciences

Molecular Dynamics Simulations Of Sodium Dodecyl Sulfate Micelle In Water: The Behavior Of Water, Chrystal Bruce, Sanjib Senapati, Max Berkowitz, L. Perera, M. Forbes Oct 2002

Molecular Dynamics Simulations Of Sodium Dodecyl Sulfate Micelle In Water: The Behavior Of Water, Chrystal Bruce, Sanjib Senapati, Max Berkowitz, L. Perera, M. Forbes

Chrystal D. Bruce

Using a 5 ns explicit atom molecular dynamics simulation of a 60 monomer sodium dodecyl sulfate micellar system containing 7579 TIP3P water molecules, the behavior of water in different electrostatic environments was examined. Structural evaluation of the system revealed that penetration of water molecules into the micelle was restricted to the headgroup region, leaving a 12 Å water-free hydrocarbon core. Water molecules near the headgroup exhibit a distortion of the water−water hydrogen bonding network due to headgroup oxygen−water hydrogen bond formation. The dynamic implications of this distortion are manifested in the decay of the dipole autocorrelation function, Φ(t) and translational …


Characterizing Gene Expression During Lens Formation In Xenopus Laevis: Evaluating The Model For Embryonic Lens Induction, Brian Walter, Jonathan Henry, Maria Carinato, Jonathan Schaefer, Adam Wolfe, Brian Walter, Kimberly Perry, Tricia Elbl May 2002

Characterizing Gene Expression During Lens Formation In Xenopus Laevis: Evaluating The Model For Embryonic Lens Induction, Brian Walter, Jonathan Henry, Maria Carinato, Jonathan Schaefer, Adam Wolfe, Brian Walter, Kimberly Perry, Tricia Elbl

Brian Walter

Few directed searches have been undertaken to identify the genes involved in vertebrate lens formation. In the frog Xenopus, the larval cornea can undergo a process of transdifferentiation to form a new lens once the original lens is removed. Based on preliminary evidence, we have shown that this process shares many elements of a common molecular/genetic pathway to that involved in embryonic lens development. A subtracted cDNA library, enriched for genes expressed during cornea-lens transdifferentiation, was prepared. The similarities/identities of specific clones isolated from the subtracted cDNA library define an expression profile of cells undergoing cornea-lens transdifferentiation ("lens regeneration") and …


Molecular Dynamics Simulation Of Sodium Dodecyl Sulfate Micelle In Water: Micellar Structural Characteristics And Counterion Distribution, Chrystal Bruce, Max Berkowitz, Lalith Perera, Malcolm Forbes Apr 2002

Molecular Dynamics Simulation Of Sodium Dodecyl Sulfate Micelle In Water: Micellar Structural Characteristics And Counterion Distribution, Chrystal Bruce, Max Berkowitz, Lalith Perera, Malcolm Forbes

Chrystal D. Bruce

An all-atom 5 nanosecond molecular dynamics simulation of a water-solvated micelle containing 60 sodium dodecyl sulfate monomers was performed. Structural properties such as the radius of gyration, eccentricity, micellar size, accessible surface area, dihedral angle distribution, carbon atom distribution, and the orientation of the monomers toward the micelle center of mass were evaluated. The results indicate a stable micellar system over the duration of the simulation. Evaluation of the structure and motion of the sodium counterions show (1) a long equilibration time (1 nanosecond) is required to achieve a stable distribution of counterions and (2) approximately 25% of the sodium …


The Spectrin-Ankyrin Skeleton Controls Cd45 Surface Display And Interleukin-2 Production, Deepti Pradhan, Jon Morrow Jan 2002

The Spectrin-Ankyrin Skeleton Controls Cd45 Surface Display And Interleukin-2 Production, Deepti Pradhan, Jon Morrow

Deepti Pradhan

With T cell receptor stimulation, intracellular pools of CD45 and spectrin move to the surface. These processes are coupled. In both peripheral lymphocytes and Jurkat T cells, βI spectrin and ankyrin associate with CD45. In Jurkat T cells, βI spectrin peptides suppress surface recruitment of CD45 and CD3 and abrogate T cell activation. Other glycoproteins such as CD43 are not altered by the spectrin peptides. Spectrin's effects are mediated by ankyrin, which binds directly to the cytoplasmic domain of CD45 (Kd = 4.3 ± 3.0 nM). These data reveal a novel and unexpected contribution of the spectrin-ankyrin skeleton to …