Premium
The R‐form of DNA does exist
Author(s) -
Shchyolkina Anna K.,
Timofeev Edward N.,
Borisova Olga F.,
Il'icheva Irina A.,
Minyat Elvira E.,
Khomyakova Elena B.,
Florentiev Vladimir L.
Publication year - 1994
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(94)80396-x
Subject(s) - dna , chemistry , computational biology , biology , biochemistry
Oligonucleotide 5'‐d(CATGCTAACT)‐L‐d(AGTTAGCATG)‐L‐d(CATGCTAACT)‐3' [L = pO(CH 2 CH 2 O) 3 P] is shown to fold back on itself twice forming at pH 7 a sufficiently stable triplex ( T m , is about 30°C) with parallel‐orientated identical strands (the recombinant or R‐form of DNA). Experimental evidence was obtained by studying thermal denaturation, chemical modification and binding of fluorescent probes. The stability of the R‐triplex increases in the presence of divalent ions or spermidine. Its structure is characterized by a certain heterogeneity that causes the cooperativity of a triplex‐to‐duplex transition to decrease. On the basis of conformational modeling, the possible types of base tripling in all four triplets are proposed. The experimental data as well as the molecular mechanic calculations indicate that the stabilities of triplets in the R‐triplex decrease in the order: G:C‐G = A:T‐A ⪢ T:A‐T > C:G‐C.