Polynucleotide Interaction

In the following chapters the complex reaction of metals with macromolecules is discussed separately for each metal ion. To conclude this series an attempt will be made to correlate metal-polynucleotide interactions with biochemical pathways. 

Table 4.II, all structures have the head-to-tail orientation, rather than the head-to-head expected in DNA. The recent isolation of head-to-head isomers is of significance for comparative purposes, and as a real model of the polynucleotide interaction [73]. The head-to-head arrangement has been extensively studied with various counteranions. In the case of the head-to-head isomers of the a>[Pt(NH3)2(9-EtG)2] cation, the dihedral angle between the bases is 72° and results in a short N7—N7 distance of 2.82 A compared to 3.9 A in DNA. However, the dihedral angles of the bases with the Pt coordination planes vary widely, depending on the...

With the increase in hardware and software, larger systems can be handled with higher accuracy. Much work will continue to be devoted to the study of proteins and polynucleotides (DNA and RNA), and particularly their interactions with more sophisticated methods. Remember proteins and genes are chemical compounds and sophisticated theoretical and chemoinformatics methods should be applied to their study - in addition to the methods developed by bioinfor-maticians. 

Messenger RNA (mRNA) (Section 28.11) A polynucleotide of ribose that reads the sequence of bases in DNA and interacts with tRNAs in the ribosomes to promote protein biosynthesis. 

Less study has been made of complexes with polydentate ligands. Ag-N linkages have been studied in relation to polynucleotide bases and the Ag-DNA interaction could be important in the use of the silver-sulphadiazine complex in burn treatment. Ethylenediamine is a bridging ligand in AgenC104 (2-coordinate silver) but essentially planar 5-coordination... 

For the anionic models, the detailed studies on their interactions with poly-and mononucleotides have not yet been carried out. However, we may say that the interactions of bases between the models and polynucleotides would be faint because of the strong electrostatic repulsive forces between the macroanions. 

The apparent hypochromieities of cationic analogs with polynucleotides are compiled in Table 2. As is clear from the table, some of the cationic models interact strongly with polynucleotides. The hypochromieities of the polymers with polynucleotides are similar to that reported for some neutral model compounds21-23, or fairly higher than those of most neutral and anionic models hitherto synthesized (see Sections 2.1. and 2.3.). The large hypoehromieity values of the cationic models... 

The important action of electrostatic forces between a cationic model and an anionic polynucleotide is clearly shown in Fig. 7. The hypochromicity sharply decreased with the ionic strength of the solution, which indicates that the base-base interactions between A12 and Poly U supported by the electrostatic attractive forces are weakened by the shielding effects of added salts. 

Tomasz, M. Mercado, C. M. Olson, J. Chatteijie, N. The mode of interaction of mitomycin C with deoxyribonucleic acid and other polynucleotides in vitro. Biochemistry 1974, 13, 4878-4887. 

Draper, P.E., and Gold, L. (1980) A method for linking fluorescent labels to polynucleotides Application to studies of ribosome-ribonucleic acid interactions. Biochemistry 19, 1774-1781. 

Rosenberg, M., Wiebers, J.L., and Gilham, P.T. (1972) Interactions of nucleotides, polynucleotides, and nucleic acids with dihydroxyboryl-subsdtuted celluloses. Biochemistry 11, 3623-3628. 

There are both geometric and kinetic differences between the interactions of A- and A-[Ru(bpy)2(hpimp)]2+ hpimp=2-(2-hydroxyphenyl)imi-dazo [4,5-/]-1,10-phenanthroline and the hexanucleotide d(GTCGAC)2. The A-isomer penetrates more deeply into the major groove of the polynucleotide it also binds more rapidly than the A-isomer to DNA (156). 

---