Linear single polynucleotide chain

The current model of the purified DNA is that it is a linear single polynucleotide chain containing a limited number of nucleotide sequence permutations, the start points of which occur within a region representing less than 6% of the genome, and also containing a terminal nucleotide sequence repetition (either inverted, natural, or both). 

C below the Tm of duplex AAV DNA. These duplex linear monomers did form duplex circular monomers and hnear dimers when exposed to annealing conditions. Thus, anneahng of intact linear AAV single polynucleotide chains led to the formation of two types of duplex linear monomers (1) those without cohesive single-stranded termini, and (2) those with cohesive single-stranded termini. 

Fig. 6. Electron micrographs of hydrogen-bonded single-stranded circles formed when purified linear heavy AAV single polynucleotide chains are exposed to annealing conditions. The arrows point to the projections observed on such single-stranded circles...

Osmium tetroxide is an electroactive marker of the polynucleotide chain and is a good probe of the DNA structure since dsDNA is modified by osmium to a much lesser extent than single-stranded polynucleotides. The limit of detection of osmium-labelled DNA was below 5 ng cm-3 after 2 min accumulation time [66]. Adsorptive stripping linear sweep voltammetry of osmium tetroxide labelled DNA at a mercury electrode [66, 67] was shown to be a good sensor for hybridization of DNA. 

The bulk of all carbohydrates in nature exists in the form of polysaccharides. These are very large molecules formed by linking together long chains of monosaccharide units. These chains may be linear, like polypeptides or polynucleotides, or branched. They may contain a single type of monosaccharide unit, similar to polyglycine or polyA for example, or two or more types of monosaccharide, like nucleic acids (four types of nucleotides) or proteins (20 types of amino acids). However, polysaccharides that contain more than two types of monosaccharide are rare in nature. 

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