Na+ selective structural switch from an intramolecular triplex to tetrad stabilised by non-canonical mispairs in double repeat of Arabidopsis thaliana telomere (T3AG3)2
DNA is polymorphic, as with four nucleobases, it can be configured in a number of secondary structures. The four-stranded DNA structures consisting of G-tetrads have especially been intriguing because of their proven existence in human cells. Due to the high prevalence of putative G-quadruplex-formi...
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2025-09-01
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2405580825002900 |
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| author | Aparna Bansal Priyanka Phogat Shrikant Kukreti |
| author_facet | Aparna Bansal Priyanka Phogat Shrikant Kukreti |
| author_sort | Aparna Bansal |
| collection | DOAJ |
| description | DNA is polymorphic, as with four nucleobases, it can be configured in a number of secondary structures. The four-stranded DNA structures consisting of G-tetrads have especially been intriguing because of their proven existence in human cells. Due to the high prevalence of putative G-quadruplex-forming sequence motifs in the human genome, scientists in recent years have highlighted the potential of exploiting these exotic structures for targeted therapies for various cancers. G-quadruplexes are the most common and well-studied arrangements of four guanines; however, other possible non-canonical arrangements of nucleobases have also been reported. Herein, using Gel electrophoresis, Circular Dichroism, UV & CD-thermal denaturation methods, and NMR, we suggested that a double repeat of Arabidopsis thaliana telomere (T3AG3)2 shows a structural switch from a non-canonical intramolecular triplex to a non-conventional tetrad other than an antiparallel G-quadruplex. This transition is mediated by increasing Na+ cation concentration from 0.1 M to 1.0 M, and the tetrad is fairly stabilised by a hydrogen-bonded cyclic array of non-canonical/mismatch base pairs (G∗G, G∗T, and T∗T). Intriguingly, such a structural transition was not manifested in the presence of K+ ions. To the best of our knowledge, such a cation-specific non-canonical structural switch, in a telomeric sequence, has not been proposed to date. |
| format | Article |
| id | doaj-art-891b6d10cef14a3ca3f3441535ebfcac |
| institution | Kabale University |
| issn | 2405-5808 |
| language | English |
| publishDate | 2025-09-01 |
| publisher | Elsevier |
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| series | Biochemistry and Biophysics Reports |
| spelling | doaj-art-891b6d10cef14a3ca3f3441535ebfcac2025-08-20T05:07:09ZengElsevierBiochemistry and Biophysics Reports2405-58082025-09-014310220310.1016/j.bbrep.2025.102203Na+ selective structural switch from an intramolecular triplex to tetrad stabilised by non-canonical mispairs in double repeat of Arabidopsis thaliana telomere (T3AG3)2Aparna Bansal0Priyanka Phogat1Shrikant Kukreti2Nucleic Acids Research Lab, Department of Chemistry, University of Delhi (North Campus), Delhi, 110007, India; Department of Chemistry, Hansraj College, University of Delhi, Delhi, 110007, IndiaNucleic Acids Research Lab, Department of Chemistry, University of Delhi (North Campus), Delhi, 110007, IndiaNucleic Acids Research Lab, Department of Chemistry, University of Delhi (North Campus), Delhi, 110007, India; Corresponding author. Nucleic Acids Research Laboratory Department of Chemistry, University of Delhi (North campus), Delhi, 110007, India.DNA is polymorphic, as with four nucleobases, it can be configured in a number of secondary structures. The four-stranded DNA structures consisting of G-tetrads have especially been intriguing because of their proven existence in human cells. Due to the high prevalence of putative G-quadruplex-forming sequence motifs in the human genome, scientists in recent years have highlighted the potential of exploiting these exotic structures for targeted therapies for various cancers. G-quadruplexes are the most common and well-studied arrangements of four guanines; however, other possible non-canonical arrangements of nucleobases have also been reported. Herein, using Gel electrophoresis, Circular Dichroism, UV & CD-thermal denaturation methods, and NMR, we suggested that a double repeat of Arabidopsis thaliana telomere (T3AG3)2 shows a structural switch from a non-canonical intramolecular triplex to a non-conventional tetrad other than an antiparallel G-quadruplex. This transition is mediated by increasing Na+ cation concentration from 0.1 M to 1.0 M, and the tetrad is fairly stabilised by a hydrogen-bonded cyclic array of non-canonical/mismatch base pairs (G∗G, G∗T, and T∗T). Intriguingly, such a structural transition was not manifested in the presence of K+ ions. To the best of our knowledge, such a cation-specific non-canonical structural switch, in a telomeric sequence, has not been proposed to date.http://www.sciencedirect.com/science/article/pii/S2405580825002900Non-canonical DNA structuresConformational switchMismatch base pairsArabidopsis thaliana |
| spellingShingle | Aparna Bansal Priyanka Phogat Shrikant Kukreti Na+ selective structural switch from an intramolecular triplex to tetrad stabilised by non-canonical mispairs in double repeat of Arabidopsis thaliana telomere (T3AG3)2 Biochemistry and Biophysics Reports Non-canonical DNA structures Conformational switch Mismatch base pairs Arabidopsis thaliana |
| title | Na+ selective structural switch from an intramolecular triplex to tetrad stabilised by non-canonical mispairs in double repeat of Arabidopsis thaliana telomere (T3AG3)2 |
| title_full | Na+ selective structural switch from an intramolecular triplex to tetrad stabilised by non-canonical mispairs in double repeat of Arabidopsis thaliana telomere (T3AG3)2 |
| title_fullStr | Na+ selective structural switch from an intramolecular triplex to tetrad stabilised by non-canonical mispairs in double repeat of Arabidopsis thaliana telomere (T3AG3)2 |
| title_full_unstemmed | Na+ selective structural switch from an intramolecular triplex to tetrad stabilised by non-canonical mispairs in double repeat of Arabidopsis thaliana telomere (T3AG3)2 |
| title_short | Na+ selective structural switch from an intramolecular triplex to tetrad stabilised by non-canonical mispairs in double repeat of Arabidopsis thaliana telomere (T3AG3)2 |
| title_sort | na selective structural switch from an intramolecular triplex to tetrad stabilised by non canonical mispairs in double repeat of arabidopsis thaliana telomere t3ag3 2 |
| topic | Non-canonical DNA structures Conformational switch Mismatch base pairs Arabidopsis thaliana |
| url | http://www.sciencedirect.com/science/article/pii/S2405580825002900 |
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