Oligomers Oligonucleotides

Rasmussen, F. W., Bendifallah, N., Zachar, V., Shiraishi, T., Fink, T., Ebbesen, P., Nielsen, P. E., and Koppelhus, U. (2006) Evaluation of transfection protocols for unmodified and modified peptide nucleic acid (PNA) oligomers. Oligonucleotides. 16,43-57. 

Oligomers Oligonucleotides Oligopeptides Oligosaccharides 10 -10 2 Less than 10 Nucleotides a-Amino acids monosaccharides... 

We have discussed modified nucleoside phosphoramidites (Section 2.1) and modified nucleoside triphosphates (Section 5.1) and their uses as the monomers for chemical or enzymatic synthesis of modified oligomers (oligonucleotides and oligodeojqmucleotides). In this section, our emphasis is primarily on interesting properties of modified oligomers. 

Oligomer (Section 14 15) A molecule composed of too few monomer units for it to be classified as a polymer but more than in a dimer trimer tetramer etc Oligonucleotide (Section 28 6) A polynucleotide containing a relatively small number of bases Oligosaccharide (Section 25 1) A carbohydrate that gives three to ten monosacchandes on hydrolysis Optical activity (Section 7 4) Ability of a substance to rotate the plane of polanzed light To be optically active a sub stance must be chiral and one enantiomer must be present in excess of the other... 

Fig. 45. (a) Introduction of M(phen)31 complex into DNA oligomers, (b). Steady-state emission spectra of modified oligonucleotides in 0.01 m sodium phosphate buffer, pH 7.0, 0.1 NaCl. Top Ru(phen)3+-modified 20-mer duplex (solid line), a 1 1 mixture of non-comple-mentary Ru(phen)3+- and Os(phen)g+-modified 20-mers (- -) and a 20-mer duplex containing Ru(phen)g+ and Ps(phen)3+groups on different strands separated by one base pair (---). Bottom 20-mer duplex with 5 -terminal Rufphen) (solid line), and Ru(phen)jf/Os(phen)3 -containing analog (---). Reproduced with permission from Ref. (157). Copyright 1998, American Chemical Society. 

Imidazolides of adenylic acid (ImpA) or uridylic acid (ImpU) are polycondensed to oligonucleotides by means of Zn2+ ions. 1673 The resulting phosphordiester bond was found to be of the 2, 5 type. In the reaction of nucleoside 5 -phosphoric acid methyl ester with ImpA in the presence of MgC, 2, 5 -dinucleotides are formed six to nine times more frequently than the corresponding 3, 5 compounds. 63 Polycondensations of ImpA in aqueous solution in the presence of various divalent metal ions lead to short oligo-adenylic acids (pA) (n = 1—5) mainly with 2, 5 -intemucleotide linkages. With Pb2+, for example, the total yield of oligomers was as high as 57%. 1683 1693... 

The donor-acceptor distance may not be unique, especially when the donor and acceptor are linked by a flexible chain (e.g. end-labeled oligomers of polymethylene or polyethylene oxide, oligopeptides, oligonucleotides, polymer chains). 

Oligomers, condensation, in formation of hy-droxo-bridged complexes, 32 91 Oligonucleotides, platinum binding, 37 185-187... 

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