Nontemplate synthesis

Figure 36. The synthesis of a [2]rotaxane with a pure hydrocarbon axle 93 reveals the strong point of the slipping process performed in the melt the nontemplate synthesis is statistical yet leads to preparative yields of 94.

S. J. Swamy, B. Veerapratap, D. Nagaraju, K. Suresh, and P. Someshwar, Nontemplate synthesis of N4 di- and tetra-amide macrocylic ligands with variable ring sizes, Tetrahedron, vol. 59, no. 50, pp. 10093-10096, 2003. 

The two complementary DNA strands have different roles in transcription. The strand that serves as template for RNA synthesis is called the template strand. The DNA strand complementary to the template, the nontemplate strand, or coding strand, is identical in base sequence to the RNA transcribed from the gene,... 

Because the nontemplate or plus (+) strand has the same base sequence as the RNA transcription product (except for the substitution of U for T), it is also called the coding strand (Figure 18.18). By convention, the direction of the gene, a segment of double-stranded DNA, is the same as the direction of the coding strand. Because the template DNA strand, also called the minus (-) strand, and the newly made RNA molecule are antiparallel, the polymerization proceeds from the 5 end to the 3 end of the gene. As noted, transcription generates several types of RNA of which rRNA, tRNA, and mRNA are directly involved in protein synthesis (Chapter 19). 

Since RNA synthesis uses only one of the two strands of DNA for a template, it is important to identify which strand is being "read." By convention, the template strand has the complementary sequence of the RNA product (with the exception of thymine in place of uracil) and the nontemplate strand has the same sequence as the RNA. The nontemplate strand is also called the coding strand because the sequence of this strand can be used to decipher the primary amino-acid sequence of an encoded protein (see Chapter 26). 

FIGURE 25-9 Nick translation. In this process, an RNA or DNA strand paired to a DNA template is simultaneously degraded by the 5 —>3 exonuclease activity of DNA polymerase I and replaced by the polymerase activity of the same enzyme. These activities have a role in both DNA repair and the removal of RNA primers during replication (both described later). The strand of nucleic acid to be removed (either DNA or RNA) is shown in green, the replacement strand in red. DNA synthesis begins at a nick (a broken phosphodiester bond, leaving a free 3 hydroxyl and a free 5 phosphate). Polymerase I extends the nontemplate DNA strand and moves the nick along the DNA—a process called nick translation. A nick remains where DNA polymerase I dissociates, and is later sealed by another enzyme. 

A number of novel methods for nanostructuring CPs have been investigated to produce materials with specific properties and functionalities for biomedical systems. The synthesis methods for nanostmctured CPs can be generally divided into two main categories, template and nontemplate approaches. 

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