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Structures and populations of conformers of nucleoside monophosphates in aqueous solution. I. General methods of conformation search with lanthanide‐ion probes and spin‐coupling constants and application to uridine‐5′‐monophosphate
Author(s) -
Inagaki Fuyuhiko,
Tasumi Mitsuo,
Miyazawa Tatsuo
Publication year - 1978
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1978.360170203
Subject(s) - chemistry , conformational isomerism , vicinal , lanthanide , coupling constant , nucleoside , aqueous solution , crystallography , relaxation (psychology) , molecule , uridine , ion , stereochemistry , computational chemistry , rna , organic chemistry , social psychology , psychology , physics , biochemistry , particle physics , gene
Abstract The Ln(III)‐induced shifts and Gd(III)‐induced changes of the spin‐lattice relaxation times were observed for the 1 H and 13 C resonances of uridine‐5′‐monophosphate (5′‐UMP) in 2 H 2 O solutions at pH 1.7–2.0. The vicinal spin‐coupling constants changed little by the addition of lanthanide cations, indicating that the conformations of this mononucleotide remained almost the same upon complex formation. A general method was worked out for conformation studies of flexible molecules with lanthanide‐ion probes and spin‐coupling constants. This method was applied in an extensive computer search for 5′‐UMP, and it was concluded that the observed Ln(III)‐induced shifts, Gd(III)‐induced changes of relaxation times, and vicinal spin‐coupling constants could only be accounted for by a mixture of conformers. The populations of the major conformers, gg ‐3′‐ endo‐anti , and gg‐2′‐ endo‐anti , amount to 46 ± 12% and 29 ± 11%, respectively. The correlation between local conformations are discussed on the basis of the present results.