Nonenzymatic polymerase-like template-directed synthesis of acyclic l-threoninol nucleic acid

Keiji Murayama,Takumi Kuriki,Hiroyuki Asanuma,Hikari Okita

doi:10.1038/s41467-021-21128-0

Abstract

Evolution of xeno nucleic acid (XNA) world essentially requires template-directed synthesis of XNA polymers. In this study, we demonstrate template-directed synthesis of an acyclic XNA, acyclicl-threoninol nucleic acid (l-aTNA), via chemical ligation mediated by N-cyanoimidazole. The ligation of an l-aTNA fragment on an l-aTNA template is significantly faster and occurs in considerably higher yield than DNA ligation. Both l-aTNA ligation on a DNA template and DNA ligation on an l-aTNA template are also observed. High efficiency ligation of trimer l-aTNA fragments to a template-bound primer is achieved. Furthermore, a pseudo primer extension reaction is demonstrated using a pool of random l-aTNA trimers as substrates. To the best of our knowledge, this is the first example of polymerase-like primer extension of XNA with all four nucleobases, generating phosphodiester bonding without any special modification. This technique paves the way for a genetic system of the l-aTNA world.

Highlights

Liu and coworkers reported that peptide nucleic acid (PNA) aldehydes could be chemically ligated on a DNA template, generating a complementary PNA strand[49]
We focused on template-mediated chemical ligation of L-aTNA as the first step of achieving the acyclic XNA world, because (1) L-aTNA is synthetically and structurally simple, (2) L-aTNA can form very stable homoduplex in an antiparallel manner, and (3) L-aTNA with clockwise helicity can form stable duplex with RNA as well as DNA
We synthesized an 8-mer L-aTNA fragment with the fluorophore Cy3 conjugated at the 3′ terminus (T8a) and a fragment carrying a phosphate at the 3′ terminus (T8b-p)

Summary

Introduction

The ligation reaction was performed at 4 °C, a temperature at which both L-aTNA and DNA strands form duplexes. F Chemical ligation yield of L-aTNA (red circles) and DNA (black circles) after indicated times of reaction. Analyzed ligation reactions of L-aTNA and DNA of different sequences (Fig. 2a).

Results

Conclusion