Fig 4.

Considerations of steric effects of the 3’-adjacent nucleotide on RNA acylation. A) Structural representation of the acylation at 2’-OH (red) of dinucleotides with NAI; B) Conformation of a dinucleotide in A-form, from a crystal structure of a 14 bp RNA duplex³³ (PDB entry 433D), showing steric congestion around the 2’-OH (marked by green arrow); C) Second-order rate constants for acylation reactions involving dinucleotides and NAI. Reacting nucleotide is shown in bold. Conditions: 30 μM dinucleotide, 100 mM NAI, 50 mM NaCl and 10 mM MOPS (pH 7), rt. DMSO content: 5% (v/v). Mean and standard deviation from 3–5 independent experiments.