Site-Selective Artificial Ribonucleases: Oligonucleotide Conjugates Containing Multiple Imidazole Residues in the Catalytic Domain

Table 1

Oligonucleotide-based artificial ribonucleases bearing multiple imidazole groups in the catalytic part: structure of conjugates and efficiencies of site-specific cleavage of yeast tRNA^Phe.

Conjugate^1		Number of Im groups	Anchor group^2	Linker length^3	Reaction rate, %/1 h^4	Reaction 1/2τ ^5
1	B-Im(2/1)	2	1/2	21	24.8	2 h 15^/*
2	B-Im(2/2)	2	2	20	25.3	2 h 5^/*
3	B-Im(4/1)	4	1	41	49.8	1 h 5^/
4a	B-Im(4/2a)	4	2	29	16.6	2 h 50^/
4b	B-Im(4/2b)	4	2	26	5.5	>12 h
5	B-Im(4/3)	4	3	18/22	~1	—^6
6	B-Im(8/1)	8	1	41	45.1	1 h 15^/
7	B-Im(8/2)	8	2	41	29.7	2 h
8	B-Im(8/2+1)	8	1	49	31.3	1 h 45^/
9	B-Im(16/1)	16	1	70	38.5	2 h 10^/
10	B-Im(8/4+1)	8	4	23/31/41	29.1	2 h
11	B-Im(12/4+2)	12	4	23/31/51	33.8	1 h 40^/
12	B-Im(24/4+2)	24	2	41/79	49.9	1 h
13	B-Im(32/4+2)	32	1	41/98	20	2 h 30^/

¹The structures of the conjugates are shown in Figure 1 and in Supplementary material (SM-Figure  1).
²The type of anchor groups of the conjugates as shown in Figure 1(a). Type 1: cyclohexanol moiety; 2: 5^/-aminothymidine residue; 3: nonnucleotide insertion; 4: 2^/-modified uridine residue.
³The number of simple C–C, C–N, or P–O bonds between the 5^/-terminal phosphate group of oligonucleotide B and imidazole groups of RNA-cleaving construct.
⁴Efficiency of the RNA cleavage was measured as percentage of tRNA^Phe cleavage at C₆₃-A₆₄ phosphodiester bond achieved after incubation during 1 h in the presence of 10 μM of the conjugate.
⁵Time to reach 50% of tRNA cleavage under the standard conditions (see above) at conjugates concentration 10⁻⁵ M.
⁶50% of tRNA^Phe cleavage was not achieved under experimental conditions.
*These conjugates are described in the preceding paper [1].