Dioxaphosphorinane-Constrained Nucleic Acid Dinucleotides as Tools for Structural Tuning of Nucleic Acids

Table 3

Comparison of melting temperatures of CNAgm or CNAgp containing duplexes.

Entry	Sequence^a	𝑇𝑚^b  °C (Δ𝑇𝑚  °C)
		𝑥=PO2^−	𝑥=𝐂𝐍𝐀𝐠𝐦	𝑥=𝐂𝐍𝐀𝐠𝐩
1	dA14/dT4TxT T4	24.2	30.1 (+5.9)	10.5 (−13.7)
2	dA14/dT6TxT T6	35.0	38.1 (+3.1)	24.0 (−11.0)
3	5′-GCGCTxT GCCG-3′; 3′-CGCGAACGGC-5′	53.0	58.0 (+5.0)	44.0 (−9.0)
4	5′-ACATTxT GAAATGCAAATG-3′; 3′-TGTAAACTTTACGTTTAC-5′	49.0	52.0 (+3.0)	44.1 (−4.9)
5	5′-ACATTTGAAATGCAAATG-3′; 3′-TGTAAACTTTACGTxT TAC-5′	49.0	54.9 (+5.9)	43.3 (−5.7)
6	5′-ACATTTGAAATGCAAATG-3′; 3′-TGTAAACTxT TACGTTTAC-5′	49.0	54.5 (+5.5)	49.0 (0.0)
7	5′-CTCATGAATATGCAAATC-3′; 3′-GAGTACTTATACGTxT TAG-5′	52.4	55.0 (+2.6)	47.2 (−5.2)
8	5′-CTCATGAATATGCAAATC-3′; 3′-GAGTACTxT ATACGTTTAG-5′	52.4	56.5 (+4.1)	47.6 (−4.8)
9	5′-TGCTCAGTAAATAATGCA-3′; 3′-ACGAGTCATTTATxT ACGT-5′	55.6	59.0 (+3.4)	49.3 (−6.3)
10	5′-TGCTCAGTAAATAATGCA-3′; 3′-ACGAGTCATxT TATTACGT-5′	55.6	58.8 (+3.2)	49.6 (−6.0)
11	5′-ATCTCATTTGAAATGCAAATGGAA-3′; 3′-TAGAGTAAACTTTACGTxT TACCTT-5′	57.9	59.3 (+1.4)	53.5 (−4.4)
12	5′-TGTCTCATGAATATGCAAATCACA-3′; 3′-ACAGAGTACTTATACGTxT TAGTGT-5′	59.9	61.3 (+1.4)	55.7 (−4.2)
13	5′-CGCGAATxT CGCG-3′; 3′-GCGCTxT AAGCGC-5′	62.0^c	58.0 (−4.0)^c	27.0 (−35.0); 82.0 (+20.0)

^aTxT : modified TT within the strand. ^bUV melting experiments were carried out in sodium phosphate buffer (10 mM, pH 7.0) containing NaCl (100 mM) and EDTA (1 mM). ^cOnly one transition observed.