Macromolecule-templated synthesis

Template or matrix polymerization can be defined as a method of polymer synthesis in which specific interactions between preformed macromolecule (template) and a growing chain are utilized. These interactions affect structure of the polymerization product (daughter polymer) and the kinetics of the process. The term template polymerization usually refers to one phase systems in which monomer, template, and the reaction product are soluble in the same solvent. 

Figure 17.6 FESEM images of polypyrrole nanofIber network (a) Low magnification image and (b) edge view of the polypyrrole nanofiber network. High magnification images of polypyrrole nanofiber network formed at (c) 120 s and (d) 1 b. (Reprinted with permission from Macromolecules, Template-Free Electrochemical Synthesis of Superhydrophilic Polypyrrole Nano fiber Network by J.F. Zhang, C. M. Li, S.J. Baoetal.,41, 19, 7053-7057. Copyright (2008) American Chemical Society)...

Shea, K.J. Thompson, E.A. Template synthesis of macromolecules. Selective fxmctiona-lization of an organic polymer. J. Org. Chem. 1978, 43, 4253 255. 

Figure 6.5 Schematic representation of an arborescent G2 copolymer template synthesis, metallic salt loading, and reduction. (Reprinted with permission from J. Dockendorff, M. Gauthier, A. Mourran and M. Moller, Arborescent amphiphilic copolymers as templates for the preparation of gold nanoparticles, Macromolecules, 41, 6621-6623. 2008 American Chemical Society.)...

K.J. Shea, E.A. Thompson, S.-D. Pandey and PS. Beauchamp, Template synthesis of macromolecules. Synthesis and chemistry of functionahsed macroporous polydivinylbenzene,... 

Papisov, l.M. (2003) The complexes of macromolecules and metal nanopartides Pseudo-template synthesis and behavior. Macromolecular Symposia, 204, 237-50. 

At this point it is necessary to make a distinction between the meanings of template and primer. The word template refers to the structural sequence of the polymerized monomeric units of a macromolecule that provides the pattern for the synthesis of another macromolecule with a complementary or characteristic sequence. The word primer, on the other hand, refers to a polymeric molecule that contains the growing point for the further addition of monomeric units. Glycogen is an example of a primer to which glucose units are added however, glycogen has no template activity. 

The synthesis of biopolymers in vivo leads to macromolecules with a defined sequence of units. This effect is very important for living organisms and is different in comparison with random copolymerization in which sequences of units are distributed according to stochastic rules. On the other hand, the predicted sequence of units can be achieved by a set of successive reactions of respective monomer molecule addition. In template copolymerization, the interaction between comonomers and the template could pre-arrange monomer units defining sequence distribution in the macromolecular product. 

Template copolymerization seems to be applied to the synthesis of copolymers with unconventional sequences of units. As it was shown, by copolymerization of styrene with oligomers prepared from p-cresyl-formaldehyde resin esterified by methacrylic or acrylic acid - short ladder-type blocks can be introduced to the macromolecule. After hydrolysis, copolymer with blocks of acrylic or methacrylic acid groups can be obtained. Number of groups in the block corresponds to the number of units in oligomeric multimonomer. Such copolymers cannot be obtained by the conventional copolymerization. 

The origin of life probably occurred in three phases (fig. 1.23) (1) The earliest phase was a period of chemical evolution during which the compounds needed for the nu-cleation of life must have been formed. These compounds include the most important class of biological macromolecules, the nucleic acids. In this phase of evolution, the synthesis of nucleic acids was noninstructed. (2) As soon as some nucleic acids were present, physical forces between them must have led to an instructed synthesis, in which the already formed molecules served as templates for the synthesis of new polymers. It seems likely that feedback loops selected out certain nucleic acids for preferential synthesis. At some point during this period of instructed synthesis more nucleic acids and possibly protein macromolecules were formed. The products of this phase of mo-... 

Proteins are informational macromolecules, the ultimate heirs of the genetic information encoded in the sequence of nucleotide bases within the chromosomes. Each protein is composed of one or more polypeptide chains, and each peptide chain is a linear polymer of amino acids. The order of the amino acids commonly found in the polypeptide chain is determined by the order of nucleotides in the corresponding messenger RNA template. In this chapter we examine four aspects of protein metabolism (fig. 29.1) (1) The process whereby amino acids are ordered and polymerized into polypeptide chains (2) posttranslational alterations in polypeptides, which occur after they are assembled on the ribosome (3) the targeting process whereby proteins move from their site of synthesis to their sites of function and (4) the proteolytic reactions that result in the return of proteins to their starting material, amino acids. 

Ultimate progress in the control of the primary structure of synthetic macromolecules might be expected if it were possible to develop a template type synthesis, in analogy to the polymerase chain reaction [27]. In spite of many efforts, no successful concept has yet been developed, which is no surprise regarding the complicated supramolecular interactions involved in the necessary steps, i.e. preorganization of the template, binding of the monomer, initiation and termination of the polymerization, and the release of the formed raacromolecule from the template [28,29]. 

Joyce GF. Nonenzymatic template-directed synthesis of informational macromolecules. Cold Spring Harb. Symp. Quant. Biol. 1987 52 41-51. 

Li Y, Yin X-F, Chen F-R, Yang H-H, Zhuang Z-X, Wang Z-R (2006) Synthesis of magnetic molecularly imprinted polymer nanowires using a nanoporous alumina template. Macromolecules 39 4497 499... 

To observe whether GVs could be loaded with nucleotides, a series of experiments was carried out demonstrating that GVs could take up, in an ethanol-dependent way, molecules such as Ca + ions or fluorescent nucleotide triphosphates. In a further attempt, the loadable microreactor could now be designed macromolecules required for mRNA synthesis by the T7 RNA polymerase (the T7 RNA polymerase and the plasmid DNA) were injected into a selected GV and YO-PRO-1 was added externally. After the fluorescence intensity (caused by the DNA template) became stable, ethanol was added and the GVs were allowed to stand for another period. Then ribonucleotides were added with a micropipet in the vicinity of the selected GV and the increase in the fluorescence intensity was followed with time (Figure 13.3). The quantification of the fluorescence increase showed that the fluorescence increased from a starting normalized value of 100 to a value after 40 min of about 220. The corresponding control experiment carried out under the same conditions but in the absence of T7 RNA polymerase shows only a modest increase in fluorescence. 

Such an answer to the riddle satisfied biochemists, geneticists, and cyberneticists alike. A mould or template for protein synthesis was predicted by the biochemical requirements, whilst, if it could be shown that the template was under genetic control, the clue to how information on protein structure is transferred from cell to cell would be found. What would be the requirements of a template It must be a macromolecule related in length to the... 

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