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Biophysical properties and thermal stability of oligonucleotides of RNA containing 7,8‐dihydro‐8‐hydroxyadenosine
Author(s) -
ChaucaDiaz Ana M.,
Jung Choi Yu,
Resendiz Marino J. E.
Publication year - 2015
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.22579
Subject(s) - rna , chemistry , oligonucleotide , circular dichroism , nucleic acid structure , biophysics , dna , protein secondary structure , base pair , lesion , crystallography , stereochemistry , biochemistry , biology , gene , psychology , psychiatry
Circular dichroism (CD) was used to assess the stabilization/destabilization imposed by oxidative lesion 7,8‐dihydro‐8‐hydroxyadenosine (8‐oxoA) on strands of RNA with different structural motifs. RNA:RNA homoduplex destabilization was observed in a position dependent manner using 10‐mers as models that displayed differences between 12.7 and 15.1°C. We found that increasing the number of modifications resulted in depressed T m values of about 12–15°C per lesion. The same effect was observed on RNA:DNA heteroduplex samples. We also tested the effects of this lesion in short hairpins containing the tetraloop UUCX (X = A, 8‐oxoA). We found that the stem was hypersensitive to substitution of A by 8‐oxoA and that it destabilized the structure by >23°C. Concomitant substitution at the stem and loop prevented formation of this secondary structure or lead to other less‐stable hairpins. Incorporation of this lesion at the first base of the loop had no effect on either structure. Overall, we found that the effects of 8‐oxoA on RNA structure are position dependent and that its stabilization may vary from sharp decreases to small increments, in some cases, leading to the formation of other more/less stable structures. These structural changes may have larger biological implications, particularly if the oxidatively modified RNA persists, thus leading to changes in RNA reactivity and function. © 2014 Wiley Periodicals, Inc. Biopolymers 103: 167–174, 2015.