Table 1.

RNA analog structures and acylation rates^a

^a The amine nucleophile is blue, and structural variation in a series is highlighted in red. Ur, uracil; Ad, adenine; Th, thymine; U, uridine; A, adenosine; T, thymidine; P, phosphate; glyc, glyceryl. For clarity, some analogs are included in more than one series.

^b k_obs are reported at 20 mM succinimidyl ester.

^c Rate is an upper limit; no product formation was detected. Two unreactive analogs, cAMP^2′-OH and U^2′-OH, were also tested but are not shown (k_obs ≤ 0.002).