biostudies-literatureKolenko PAkademie Věd České RepublikyMinisterstvo Školství, Mládeže a TělovýchovyČeské Vysoké Učení Technické v Praze1233-1243https://www.ebi.ac.uk/biostudies/studies/S-EPMC7709200biostudies-literatureUnknown76(Pt 12)Solution and crystal data are reported for DNA 18-mers with sequences related to those of bacterial noncoding single-stranded DNA segments called repetitive extragenic palindromes (REPs). Solution CD and melting data showed that the CG-rich, near-palindromic REPs from various bacterial species exhibit dynamic temperature-dependent and concentration-dependent equilibria, including architectures compatible with not only hairpins, which are expected to be biologically relevant, but also antiparallel duplexes and bimolecular tetraplexes. Three 18-mer oligonucleotides named Hpar-18 (PDB entry 6rou), Chom-18 (PDB entry 6ros) and its brominated variant Chom-18Br (PDB entry 6ror) crystallized as isomorphic right-handed A-like duplexes. The low-resolution crystal structures were solved with the helActa crystallographica. Section D, Structural biologyStructural variability of CG-rich DNA 18-mers accommodating double T-T mismatches.PMC7709200LTAUSA18197LM2018127LM2015043SGS19/189/OHK4/3T/14CZ.02.1.01/0.0/0.0/16_013/0001776RVO 86652036CZ.1.05/1.1.00/02.0109Cerny JSvoboda JSchneider BCharnavets TKolenko PfalseStructural variability of CG-rich DNA 18-mers accommodating double T-T mismatches.Solution and crystal data are reported for DNA 18-mers with sequences related to those of bacterial noncoding single-stranded DNA segments called repetitive extragenic palindromes (REPs). Solution CD and melting data showed that the CG-rich, near-palindromic REPs from various bacterial species exhibit dynamic temperature-dependent and concentration-dependent equilibria, including architectures compatible with not only hairpins, which are expected to be biologically relevant, but also antiparallel duplexes and bimolecular tetraplexes. Three 18-mer oligonucleotides named Hpar-18 (PDB entry 6rou), Chom-18 (PDB entry 6ros) and its brominated variant Chom-18Br (PDB entry 6ror) crystallized as isomorphic right-handed A-like duplexes. The low-resolution crystal structures were solved with the hel2020-01-01T00:00:00Z2020 Dec2026-04-30T08:10:03.068Z2026-04-07T15:56:46.715ZS-EPMC77092003326332910.1107/S2059798320014151