Extended Data Fig. 7: Chemoselective two-step biomimetic peptide synthesis.
From: Thioester-mediated RNA aminoacylation and peptidyl-RNA synthesis in water
The reaction of adenosine 16A (20 mM), N-acetyl-glycine thioacid 11Gly (240 mM) and alanine thioester l-\({{\bf{1}}}_{{\bf{A}}{\bf{l}}{\bf{a}}}^{{\bf{e}}}\) (240 mM) in MES buffer (500 mM, pH 6.5) at room temperature yields: (i) no amidoacyl-RNA, when K3Fe(CN)6 (600 mM) was added after 30 min; l-\({{\bf{1}}}_{{\bf{A}}{\bf{l}}{\bf{a}}}^{{\bf{e}}}\) was the only amine after 30 min, so Ac-Gly-Ala-SEt (\({{\bf{39}}}_{{\bf{G}}{\bf{l}}{\bf{y}}{\bf{A}}{\bf{l}}{\bf{a}}}^{{\bf{e}}}\)) was observed as the only peptide product and \({{\bf{39}}}_{{\bf{G}}{\bf{l}}{\bf{y}}{\bf{A}}{\bf{l}}{\bf{a}}}^{{\bf{e}}}\) does not react with 16A (also see Extended Data Fig. 6); (ii) aminoacyl-RNA \({{\bf{17}}}_{{\bf{A}}{\bf{l}}{\bf{a}}}^{{\bf{A}}}\) (21%) after 24 h; and (iii) \({{\bf{17}}}_{{\bf{A}}{\bf{l}}{\bf{a}}}^{{\bf{A}}}\) formed in situ then furnishes peptidyl-RNA \({{\bf{40}}}_{{\bf{A}}{\bf{l}}{\bf{a}}{\bf{G}}{\bf{l}}{\bf{y}}{\bf{A}}{\bf{c}}}^{{\bf{A}}}\) (98%) in near-quantitative yield, when K3Fe(CN)6 (600 mM) was added after 24 h. For chemoselective one-pot peptidyl-RNA synthesis with Arg 33, see Fig. 6c.
