Fig. 5: Thioester-mediated synthesis of aminoacyl nucleosides.
From: Thioester-mediated RNA aminoacylation and peptidyl-RNA synthesis in water
1H NMR spectra showing various reactions. a, NCA l-4Ala (20 mM) in MES buffer (200 mM; 3.99 ppm), at pH 5.0 and room temperature, which yields: (1) alanine l-\({{\bf{1}}}_{{\bf{A}}{\bf{l}}{\bf{a}}}^{{\bf{c}}}\) (>90%) without (coenzyme M) thiol 5c, and (2) alanine thioester l-\({{\bf{1}}}_{{\bf{A}}{\bf{l}}{\bf{a}}}^{{\bf{c}}}\) (86%) with thiol 5c (100 mM), the aminoacyl-thiol product is highly stable at pH 5.0. b, Adenosine 16A (20 mM) and NCA l-4Ala (600 mM) at pH 6.5 and room temperature, for which no nucleoside aminoacylation was observed. Adenosine 16A (20 mM), NCA l-4Ala (600 mM) and thiol 5c (1 M) at pH 6.5 and room temperature, which furnished alanyl-adenosine \({{\bf{17}}}_{{\bf{A}}{\bf{l}}{\bf{a}}}^{{\bf{A}}}\) (35%) from the reaction of adenosine (16A) with aminoacyl-thiol (l-\({{\bf{1}}}_{{\bf{A}}{\bf{l}}{\bf{a}}}^{{\bf{c}}}\)) formed in situ in water. R1 = CH2CH2SO3H. c, Adenosine 16A (20 mM), aspartate-anhydride 34Asp (600 mM) and thiol 3c (1 M) at pH 6.5 and room temperature after (1) 0.5 days and (2) 5 days, which furnished aspartyl-adenosine \({{\bf{17}}}_{{\bf{A}}{\bf{s}}{\bf{p}}}^{{\bf{A}}}\) from the reaction of adenosine (16A) with aminoacyl-thiol l-\({{\bf{1}}}_{{\bf{A}}{\bf{s}}{\bf{p}}}^{{\bf{c}}}\) formed in situ in water. d, Incubation of prebiotically plausible α-aminonitrile 8Ala (2 mM) and thiol 5b (10 mM) in frozen sodium phosphate solution (pH 7.0, 50 mM) at −7 °C for 30 days yields aminoacyl-thiol \({{\bf{1}}}_{{\bf{A}}{\bf{l}}{\bf{a}}}^{{\bf{b}}}\) in 48% yield at neutral pH.
