Chain conformation nucleotides

Yathindra N, Sundaralingam M (1973) Correlations between the backbone and side chain conformations in 5 -nucleotides. The concept of a rigid nucleotide conformation. Biopolymers 12 297-314... 

The process of RNA synthesis in bacteria—depicted in Figure 37-3—involves first the binding of the RNA holopolymerase molecule to the template at the promoter site to form a PIC. Binding is followed by a conformational change of the RNAP, and the first nucleotide (almost always a purine) then associates with the initiation site on the 3 subunit of the enzyme. In the presence of the appropriate nucleotide, the RNAP catalyzes the formation of a phosphodiester bond, and the nascent chain is now attached to the polymerization site on the P subunit of RNAP. (The analogy to the A and P sites on the ribosome should be noted see Figure... 

Ci0HuN5O10P2- C4H12N03+ 2 H20 Adenosine 5 -[tris(hydroxy-methyl)methylammonium diphosphate], dihydrate (HMADPH)203 P2i Z = 2 Dx = 1.65 R = 0.047 for 1,624 reflections. The disposition of the base is anti (75.5°). The D-ribosyl group is T (183.0°, 35.4°) and the orientation about the exocyclic, C-4 - C-5 bond is gauche + (53.7 °). These features are similar to those of the favored conformations adopted by the nucleotide monophosphates. The pyrophosphate chain displays... 

DNA is a structurally polymorphic macromolecule which, depending on nucleotide sequence and environmental conditions, can adopt a variety of conformations. The double helical structure of DNA (dsDNA) consists of two strands, each of them on the outside of the double helix and formed by alternating phosphate and pentose groups in which phosphodiester bridges provide the covalent continuity. The two chains of the double helix are held... 

NUCLEOTIDES AND NUCLEIC ACIDS Abbreviations and symbols for nucleic acids, polynucleotides and their constituents /. Biol. Chem. (1970) 245, 5171-5176 Corrections, J. Biol Chem. (1971) 246, 4894 Abbreviations and symbols for the description of conformations of polynucleotide chains Eur. J. Biochem. (1983) 131, 9-15 Nomenclature for incompletely specified bases in nucleic acid sequences... 

Theoretical conformational analysis provides a basis for understanding the unique features of double-stranded DNA In terms of its chemical architecture. The well-known stiffness of the chain as a whole derives from the sequence of heterocyclic bases, while the local mobility of the constituent nucleotides reflects the structural complexity of the sugar-phosphate backbone. 

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