α -d-2 ′ -Deoxyadenosine, an irradiation product of canonical DNA and a component of anomeric nucleic acids: crystal structure, packing and Hirshfeld surface analysis

α -d-2 ′ -Deoxyribonucleosides are products of the γ -irradiation of DNA under oxygen-free conditions and are constituents of anomeric DNA. They are not found as natural building blocks of canonical DNA. Reports on their conformational properties are limited. Herein, the single-crystal X-ray structure of α -d-2 ′ -deoxyadenosine ( α -dA), C10H13N5O3, and its conformational parameters were determined. In the crystalline state, α -dA forms two conformers in the asymmetric unit which are connected by hydrogen bonds. The sugar moiety of each conformer is arranged in a `clamp'-like fashion with respect to the other conformer, forming hydrogen bonds to its nucleobase and sugar residue. For both conformers, a syn conformation of the nucleobase with respect to the sugar moiety was found. This is contrary to the anti conformation usually preferred by α -nucleosides. The sugar conformation of both conformers is C2 ′ -endo, and the 5 ′ -hydroxyl groups are in a +sc orientation, probably due to the hydrogen bonds formed by the conformers. The formation of the supramolecular assembly of α -dA is controlled by hydrogen bonding and stacking interactions, which was verified by a Hirshfeld and curvedness surface analysis. Chains of hydrogen-bonded nucleobases extend parallel to the b direction and are linked to equivalent chains by hydrogen bonds involving the sugar moieties to form a sheet. A comparison of the solid-state structures of the anomeric 2 ′ -deoxyadenosines revea...

Source: Acta Crystallographica Section C - January 22, 2024 Category: Chemistry Authors: Leonard, P. Zhang, A. Budow-Busse, S. Daniliuc, C. Seela, F. Tags: α -2 ′ -deoxyadenosine anomer crystal structure crystal packing nucleoside Hirshfeld surface analysis research papers Source Type: research