Manganese(II) promotes prebiotically plausible non-enzymatic RNA ligation reactions

Abstract

Using different prebiotically plausible activating reagents, the RNA ligation yield was significantly increased in the presence of Mn(II). The mechanism of the activation reaction has been investigated using 5'-AMP as an analogue.

Scheme 1. (a) Chemical structures of activation reagents and organocatalysts. (b) Proposed intermediates for RNA ligation reactions. (c) Passerini product and azole-5′-AMP products. (d) Reaction scheme of cyanogen chloride with 5′-AMP in the presence of azoles.

Fig. 1. PAGE analysis of in situ nicked-duplex RNA ligation using 5′-pUACUGGCA-Cy3 (10 μM), 5′-GAGAACC (20 μM), 5′-CCAGUAGGUUCUC (10 μM), 1-MeIm (100 mM), KCN (50 mM), sodium hypochlorite (20 mM), pH value was 6, (a) before sodium hypochlorite was added; (b) with MgCl₂ (10 mM), incubated for 2 hours; (c) with MnCl₂ (10 mM), incubated for 2 hours; (d) same as b, incubated for 24 hours; (e) same as c, incubated for 24 hours.

Fig. 2. Stacked ³¹P-NMR spectra of a solution of 5′-AMP (10 mM), 1-MeIm (100 mM), potassium cyanide (50 mM), sodium hypochlorite (20 mM). The chemical shift drift of the signal for 5′-AMP was caused by changing pH.