Electrophoresis of a soft toroid of nonuniform structure

Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan.
Colloids and surfaces B: Biointerfaces (Impact Factor: 4.15). 05/2012; 98:36-42. DOI: 10.1016/j.colsurfb.2012.04.019
Source: PubMed


The electrophoresis of a nonuniformly structured soft particle is modeled theoretically by considering an isolated soft toroid comprising a rigid core and a polyelectrolyte layer with exponential segment distribution. The influences of the thickness of double layer, and the fixed charge density, the friction coefficient, the uniformity, and the thickness of the polyelectrolyte layer on the electrophoresis behavior of the toroid are examined. We show that for a specified fixed charge density, the electrophoresis mobility of the toroid increases with increasing double layer thickness, and the higher that density the larger the mobility. The thicker the polyelectrolyte layer and/or more uniform the segment distribution of that layer the higher the fixed charge density, yielding a larger mobility. The thicker the double layer the more significant is the influence of the polyelectrolyte layer structure of a toroid on its mobility.

4 Reads
  • [Show abstract] [Hide abstract]
    ABSTRACT: RECENT studies have revealed that the packaging of DNA into phage heads is an ordered sequence of structural and biochemical events rather than a simple, spontaneous self-assembly of component molecules. In the assembly of T7 for example1, heads containing the products of genes 8-10 and 14-16 are apparently formed first. Gene 9 protein is removed from the heads before or during the incorporation of DNA. At least two other gene products which play no direct structural role are required for the maturation of the heads. A somewhat similar situation exists for phage λ, which has been shown to require ATP for the in vitro packaging of DNA into preformed heads (petite λ)2.
    Nature 02/1976; 259(5541):333-5. DOI:10.1038/259333a0 · 41.46 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Studies of the organization of double-stranded DNA within bacteriophage heads during the past four decades have produced a wealth of data. However, despite the presentation of numerous models, the true organization of DNA within phage heads remains unresolved. The observations of toroidal DNA structures in electron micrographs of phage lysates have long been cited as support for the organization of DNA in a spool-like fashion. This particular model, like all other models, has not been found to be consistent will all available data. Recently we proposed that DNA within toroidal condensates produced in vitro is organized in a manner significantly different from that suggested by the spool model. This new toroid model has allowed the development of an alternative model for DNA organization within bacteriophage heads that is consistent with a wide range of biophysical data. Here we propose that bacteriophage DNA is packaged in a toroid that is folded into a highly compact structure.
    Biophysical Journal 11/1995; 69(4):1355-62. DOI:10.1016/S0006-3495(95)80002-0 · 3.97 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The morphologies of DNA complexes obtained using the diblock copolymer series DMAXMPC30 using transmission electron microscopy (TEM) and liquid atomic force microscopy (AFM) was analyzed. Enzymatic degradation assays revealed that only the DMA homopolymer provided effective DNA protection against DNase I degradation. TEM study analyzed that the morphology of the complexes changes from loosely condensed structures to highly condensed rods, torroids and oval shaped particles as the DMA moiety increases. For DMA40-MPC30 and DMA60MPC30 complexes, gel electrophoretic and TEM data indicated high levels of DNA condensation.
    Langmuir 05/2005; 21(8):3591-8. DOI:10.1021/la047480i · 4.46 Impact Factor
Show more