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The surprising pairing of 2‐aminoimidazo[1,2‐ a ][1,3,5]triazin‐4‐one, a component of an expanded DNA alphabet
Author(s) -
Laos Roberto,
Lampropoulos Christos,
Benner Steven A.
Publication year - 2019
Publication title -
acta crystallographica section c
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 17
ISSN - 2053-2296
DOI - 10.1107/s2053229618016923
Subject(s) - nucleobase , tautomer , nucleotide , dna , molecular structure of nucleic acids: a structure for deoxyribose nucleic acid , nucleic acid , base pair , chemistry , crystallography , stereochemistry , alphabet , acceptor , physics , biochemistry , gene , linguistics , philosophy , condensed matter physics
Synthetic biologists demonstrate their command over natural biology by reproducing the behaviors of natural living systems on synthetic biomolecular platforms. For nucleic acids, this is being done stepwise, first by adding replicable nucleotides to DNA, and then removing its standard nucleotides. This challenge has been met in vitro with `six‐letter' DNA and RNA, where the Watson–Crick pairing `concept' is recruited to increase the number of independently replicable nucleotides from four to six. The two nucleobases most successfully added so far are Z and P , which present a donor–donor–acceptor and an acceptor–acceptor–donor pattern, respectively. This pair of nucleobases are part of an `artificially expanded genetic information system' (AEGIS). The Z nucleobase has been already crystallized, characterized, and published in this journal [Matsuura et al. (2016). Acta Cryst. C 72 , 952–959]. More recently, variants of Taq polymerase have been crystallized with the pair P : Z trapped in the active site. Here we report the crystal structure of the nucleobase 2‐aminoimidazo[1,2‐ a ][1,3,5]triazin‐4‐one (trivially named P ) as the monohydrate, C 5 H 5 N 5 O·H 2 O. The nucleobase P was crystallized from water and characterized by X‐ray diffraction. Interestingly, the crystal structure shows two tautomers of P packed in a Watson–Crick fashion that cocrystallized in a 1:1 ratio.