The R‐form of DNA does exist

FEBS Letters

Borisova, Olga F.¹  Il'icheva, Irina A.¹  Florentiev, Vladimir L.¹  Khomyakova, Elena B.¹  Minyat, Elvira E.¹  Shchyolkina, Anna K.¹  Timofeev, Edward N.¹ 

[1] V.A. Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilova str., 32, 117984 Moscow, Russian Federation

关键词: DNA triplex;    Recombination;    Arbitrary sequence;    parARB;    5'-d(CATGCTAACT)-pO(CH2CH2O)3p-d(A-GTTAGCATG)-pO(CH2CH2O)3p-d-(CATGCTAACT)-3';   

DOI  :  10.1016/0014-5793(94)80396-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Oligonucleotide 5'-d(CATGCTAACT)-L-d(AGTTAGCATG)-L-d(CATGCTAACT)-3' [L = pO(CH₂CH₂O)₃P] 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.

【 授权许可】

Unknown