Conformational guanosine phosphates

Scheme 2. Conformational changes of the y-phosphate in a) phosphoryl-transfer reaction transition state K), and various species of AlFx b) AlF41, c) A1C13. Dotted lines indicate that the degree of bond making and bond breaking determines whether the transition is more dissociative, with a metaphosphate-like intermediate, or associative, with a pentavalent intermediate. Charges have been omitted for clarity. N = adenosine or guanosine. According to [16, 17, 21]...

RNase T1 cleaves 3 of guanosines leaving a 3 phosphate. It recognises the syn conformation of guanosines explaining the strong preference for guanosines in terminal loops. 

Conformation of Guanosine and Adenosine Phosphates in Small-Molecule and Ligand/Protein Crystal Structures... 

Circular dichroism of pyrophosphate derivatives of some purine nucleosides indicates a symmetrically stacked syn conformation except when there is restricted rotation of the base. Circular dichroism has also been used to study the inhibitor action of guanosine 2 (3 )-mono-phosphate on a ribonuclease. ... 

Tian-Dinh S, Thieiy J, Guschlbauer J-J (1972) Nucleoside conformations. VIII. Conframation of guanosine 2 -phosphate in aqueous solution by proton magnetic resonance spectroscopy. Biochim Biophys Acta 281 289—298... 

Syntheses of the adenosine and guanosine 5 -phosphoroazidates (622) and (613), which were required as affinity labels, of P -di([ C]adenosine-5 )penta-phosphate, an inhibitor of adenylate kinase (E.C. 2.7.4.3), and, by improved procedures, of 3 -deoxyadenosine (cordycepin) 5 -triphosphate have been reported. 2 -Deoxy-2 -deuterio-adenosine (276) (see p. 100) and its 2 -epimer have been converted into the corresponding 3, 5 -phosphates, whose conformers were examined by H n.m.r. spectroscopy." ... 

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