Template packing

Pander J W and F M Richards 1987. Tertiary Templates for Proteins. Use of Packing Criteria in Enumeration of Allowed Sequences for Different Structural Classes. Journal of Molecular Bio 193 775-791. 

JW Ponder, FM Richards. Tertiary templates for proteins Use of packing criteria m the enumeration of allowed sequences for different structural classes. J Mol Biol 193 775-792, 1987. 

New templated polymer support materials have been developed for use as re versed-phase packing materials. Pore size and particle size have not usually been precisely controlled by conventional suspension polymerization. A templated polymerization is used to obtain controllable pore size and particle-size distribution. In this technique, hydrophilic monomers and divinylbenzene are formulated and filled into pores in templated silica material, at room temperature. After polymerization, the templated silica material is removed by base hydrolysis. The surface of the polymer may be modified in various ways to obtain the desired functionality. The particles are useful in chromatography, adsorption, and ion exchange and as polymeric supports of catalysts (39,40). 

In the elucidation of retention mechanisms, an advantage of using enantiomers as templates is that nonspecific binding, which affects both enantiomers equally, cancels out. Therefore the separation factor (a) uniquely reflects the contribution to binding from the enantioselectively imprinted sites. As an additional comparison the retention on the imprinted phase is compared with the retention on a nonimprinted reference phase. The efficiency of the separations is routinely characterized by estimating a number of theoretical plates (N), a resolution factor (R ) and a peak asymmetry factor (A ) [19]. These quantities are affected by the quality of the packing and mass transfer limitations, as well as of the amount and distribution of the binding sites. 

The use of DNA as a template to fabricate mesoscale structures was also demonstrated in a recent work of Torimoto and coworkers. They used preformed, positively charged 3-nm CdS nanoparticles with a thiocholine-modified surface to be assembled into chains by using the electrostatic interaction between positively charged nanoparticle snr-faces and the phosphate groups of DNA. As determined by TEM analysis, the CdS nanoparticles were arranged in a qnasi-one-dimensional dense packing. This revealed interparticle distances of about 3.5 nm, which is almost equal to the height of one helical tnm of the DNA double strand [98]. 

Fig. 8.5 SEM images of (A) close packed array of latex beads (scale bar= 1 tm) and (B) macroporous aminopropyl-functionalized magnesium phyllosilicate monolith obtained after infiltration and extraction of colloidal template (scale bar= 1 pm).

Figure 8. The 2D herringbone packing motif in (a) naphthalene, (b) biphenyl, and (c) anthracene as viewed normal to the ab plane, (d) Anticipated 1 3 pillar (black)-guest (grey) herringbone packing within the gallery regions of a templated...

One of the first attempts to explain e.s. was made by Wells and coworkers [234], who proposed that the L-shaped modifier could generate a chiral surface, by adsorption on Pt in ordered nonclose-packed arrays, allowing preferential adsorption on the metal surface of one of the faces of the prochiral substrate (template model). 

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