Abstract
The tetradeoxyribonucleotide pAGCG in 1 M NaCl forms duplexes with terminal non‐canonical pA·G pairs with stability significantly exceeding that for the duplex (pAGCT)2 and lower than that for the duplex (pCGCG)2. The deoxyriboduplex (pAGCG)2 is considerably stabilized by 3′‐ and slightly by 5′‐ dangling bases. Therefore, the stability of duplexes with 3′ dangling bases decreases in the order (pAGCG)2>(pCGCG)2>(pAGCT)2. The sum of the independent stabilizing effect of the of 5′‐p and 3′‐ dangling bases on the (pAGCG)2 core duplex is higher than that of the additional terminal pG·A pair in pG‐A‐/‐G‐A tandem of the duplex (pAGCG)2.