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Interaction of metal ions with polynucleotides and related compounds. X. Studies on the reaction of silver(I) with the nucleosides and polynucleotides, and the effect of silver(I) on the zinc(II) degradation of polynucleotides
Author(s) -
Eichhorn Gunther L.,
Butzow James J.,
Clark Patricia,
Tarien Edward
Publication year - 1967
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.1967.360050306
Subject(s) - polynucleotide , chemistry , cytidine , zinc , guanosine , uridine , potentiometric titration , metal , titration , inosine , inorganic chemistry , metal ions in aqueous solution , polymer chemistry , rna , adenosine , organic chemistry , biochemistry , ion , gene , enzyme
Potentiometric titration curves of the silver(I) complexes of cytidine, adenosine, and uridine show little uptake of base below pH 7, unlike the curve for silver(I)‐guanosine, which shows extensive base uptake at neutral pH. This observation is correlated with spectrophotometric data showing little difference between the silver complex spectra of adenosine, cytidine, and uridine and the spectra of uncomplexed nucleosides, except at high pH, but showing a great difference between the silver complex spectra of guanosine and inosine and the corresponding uncomplexed nucleosides even at pH 6. Similar comparisons of the silver complexes of poly A, poly C, poly I, and poly U, both by potentiometric titration and by spectrophotometry, show that poly I behaves like guanosine and inosine as expected, differing from poly A and poly C. However, poly U behaves like poly I and thus does not resemble uridine in its complexing behavior. There is thus a dichotomy between poly A and poly C on the one hand in silver complexing phenomena, compared with poly U and poly I on the other. When silver(I) is added to systems containing zinc(II) and various polynucleotides, the same dichotomy is noted. Silver(I) inhibits the degradation by zinc(II) of all four polynucleotides, but the degradation of poly I and poly U is prevented virtually completely. Silver(I) alone has no degradative effect on RNA and inhibits, the zinc(II) degradation of RNA. Polynucleotide complexes in which silver(I) and zinc(II) are simultaneously bound to different positions on the macromolecules are postulated as intermediates in the inhibited degradation reactions.