Special Issue "Design, Synthesis, and Structures of Modified RNA/DNA Bases"

A special issue of Crystals (ISSN 2073-4352). This special issue belongs to the section "Biomolecular Crystals".

Deadline for manuscript submissions: closed (30 June 2020) | Viewed by 1918

Special Issue Editor

Prof. Dr. Gustavo Portalone
E-Mail Website
Guest Editor
Structural Chemistry Research Group and X-ray Diffraction Laboratory, Chemistry Department, "Sapienza" University of Rome, 00191 Roma, Italy
Interests: supramolecular chemistry; crystal engineering; canonical and epigenetic nucleobases; hydrogen bond; halogen bond; X-ray single-crystal; X-ray powder diffraction; theoretical calculations; AFM
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Special Issue Information

Dear Colleagues,

Naturally occurring modified nucleobases, next to the five canonical nucleobases, extend the chemical information content of DNA and RNA. They are known to exert profound effects in a variety of microbiological and mammalian systems as they can be readily incorporated into DNA. Nonetheless, their role in regulating the basic functions in a cell is still largely unexplored. Moreover, over the past two decades, chemically modified nucleobases have been developed as a versatile tool for chemical fine-tuning of artificial DNA in the emerging area of synthetic biology. Indeed, unnatural base pairing may possess higher specificity and thermal stability through a suitable design of artificial nucleobases and yield an artificially expanded genetic information system.

While the emphasis of this Special Issue on the “Design, Synthesis, and Structures of Modified RNA/DNA Bases” is the rational design of new crystal and cocrystal structures of unnatural and epigenetic nucleobases, also including their drug complexes, from X-ray and/or neutron diffraction methods, theoretical analyses are also appropriate.

As Guest Editor, it is my pleasure to invite you to contribute to this issue. Regular articles, communications, as well as reviews are all welcome.

Prof. Dr. Gustavo Portalone
Guest Editor

Manuscript Submission Information

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  • Noncanonical DNA base
  • Noncanonical RNA base
  • Noncanonical base-pairing
  • Noncovalent interactions
  • Crystal structure
  • Quantum chemical calculations
  • Energetics and structure prediction

Published Papers (1 paper)

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5-Fluorocytosine/Isocytosine Monohydrate. The First Example of Isomorphic and Isostructural Co-Crystal of Pyrimidine Nucleobases
Crystals 2020, 10(11), 999; https://doi.org/10.3390/cryst10110999 - 03 Nov 2020
Cited by 5 | Viewed by 1565
To date, despite the crucial role played by cytosine, uracil, and thymine in the DNA/RNA replication process, no examples showing isomorphic and isostructural behavior among binary co-crystals of natural or modified pyrimidine nucleobases have been so far reported in the literature. In view [...] Read more.
To date, despite the crucial role played by cytosine, uracil, and thymine in the DNA/RNA replication process, no examples showing isomorphic and isostructural behavior among binary co-crystals of natural or modified pyrimidine nucleobases have been so far reported in the literature. In view of the relevance of biochemical and pharmaceutical compounds such as pyrimidine nucleobases and their 5-fluoroderivatives, co-crystals of the molecular complex formed by 5-fluorocytosine and isocytosine monohydrate, C4H4FN3O·C4H5N3O·H2O, have been synthesized by a reaction between 5-fluorocytosine and isocytosine. They represent the first example of isomorphic and isostructural binary co-crystals of pyrimidine nucleobases, as X-ray diffraction analysis shows structural similarities in the solid-state organization of molecules with that of the (1:1) 5-fluorocytosine/5-fluoroisocytosine monohydrate molecular complex, which differs solely in the H/F substitution at the C5 position of isocytosine. Molecules of 5-fluorocytosine and isocytosine are present in the crystal as 1H and 3H-ketoamino tautomers, respectively. They form almost coplanar WC base pairs through nucleobase-to-nucleobase DAA/ADD hydrogen bonding interactions, demonstrating that complementary binding enables the crystallization of specific tautomers. Additional peripheral hydrogen bonds involving all available H atom donor and acceptor sites of the water molecule give a three-dimensional polymeric structure. In the absence of H⋯F hydrogen-bonding interactions, the robustness of the supramolecular architectures based on three-point recognition synthons is responsible for the existence of isostructurality between the two molecular complexes. Full article
(This article belongs to the Special Issue Design, Synthesis, and Structures of Modified RNA/DNA Bases)
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