Spectroscopic Characterization of Mitochondrial G-Quadruplexes
Guanine quadruplexes (G4s) are highly polymorphic four-stranded structures formed within guanine-rich DNA and RNA sequences that play a crucial role in biological processes. The recent discovery of the first G4 structures within mitochondrial DNA has led to a small revolution in the field. In partic...
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2022-01-01
|
| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/23/2/925 |
| _version_ | 1797493241933725696 |
|---|---|
| author | Sara Illodo Cibrán Pérez-González Ramiro Barcia Flor Rodríguez-Prieto Wajih Al-Soufi Mercedes Novo |
| author_facet | Sara Illodo Cibrán Pérez-González Ramiro Barcia Flor Rodríguez-Prieto Wajih Al-Soufi Mercedes Novo |
| author_sort | Sara Illodo |
| collection | DOAJ |
| description | Guanine quadruplexes (G4s) are highly polymorphic four-stranded structures formed within guanine-rich DNA and RNA sequences that play a crucial role in biological processes. The recent discovery of the first G4 structures within mitochondrial DNA has led to a small revolution in the field. In particular, the G-rich conserved sequence block II (CSB II) can form different types of G4s that are thought to play a crucial role in replication. In this study, we decipher the most relevant G4 structures that can be formed within CSB II: RNA G4 at the RNA transcript, DNA G4 within the non-transcribed strand and DNA:RNA hybrid between the RNA transcript and the non-transcribed strand. We show that the more abundant, but unexplored, G6AG7 (37%) and G6AG8 (35%) sequences in CSB II yield more stable G4s than the less profuse G5AG7 sequence. Moreover, the existence of a guanine located 1 bp upstream promotes G4 formation. In all cases, parallel G4s are formed, but their topology changes from a less ordered to a highly ordered G4 when adding small amounts of potassium or sodium cations. Circular dichroism was used due to discriminate different conformations and topologies of nucleic acids and was complemented with gel electrophoresis and fluorescence spectroscopy studies. |
| first_indexed | 2024-03-10T01:17:12Z |
| format | Article |
| id | doaj.art-8335a71541b74af6852faa61531420b1 |
| institution | Directory Open Access Journal |
| issn | 1661-6596 1422-0067 |
| language | English |
| last_indexed | 2024-03-10T01:17:12Z |
| publishDate | 2022-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | International Journal of Molecular Sciences |
| spelling | doaj.art-8335a71541b74af6852faa61531420b12023-11-23T14:06:41ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672022-01-0123292510.3390/ijms23020925Spectroscopic Characterization of Mitochondrial G-QuadruplexesSara Illodo0Cibrán Pérez-González1Ramiro Barcia2Flor Rodríguez-Prieto3Wajih Al-Soufi4Mercedes Novo5Departamento de Química Física, Facultade de Ciencias, Universidade de Santiago de Compostela, 27002 Lugo, SpainDepartamento de Química Física, Facultade de Ciencias, Universidade de Santiago de Compostela, 27002 Lugo, SpainDepartamento de Bioquímica e Bioloxía Molecular, Facultade de Veterinaria, Universidade de Santiago de Compostela, 27002 Lugo, SpainCentro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Departamento de Química Física, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, SpainDepartamento de Química Física, Facultade de Ciencias, Universidade de Santiago de Compostela, 27002 Lugo, SpainDepartamento de Química Física, Facultade de Ciencias, Universidade de Santiago de Compostela, 27002 Lugo, SpainGuanine quadruplexes (G4s) are highly polymorphic four-stranded structures formed within guanine-rich DNA and RNA sequences that play a crucial role in biological processes. The recent discovery of the first G4 structures within mitochondrial DNA has led to a small revolution in the field. In particular, the G-rich conserved sequence block II (CSB II) can form different types of G4s that are thought to play a crucial role in replication. In this study, we decipher the most relevant G4 structures that can be formed within CSB II: RNA G4 at the RNA transcript, DNA G4 within the non-transcribed strand and DNA:RNA hybrid between the RNA transcript and the non-transcribed strand. We show that the more abundant, but unexplored, G6AG7 (37%) and G6AG8 (35%) sequences in CSB II yield more stable G4s than the less profuse G5AG7 sequence. Moreover, the existence of a guanine located 1 bp upstream promotes G4 formation. In all cases, parallel G4s are formed, but their topology changes from a less ordered to a highly ordered G4 when adding small amounts of potassium or sodium cations. Circular dichroism was used due to discriminate different conformations and topologies of nucleic acids and was complemented with gel electrophoresis and fluorescence spectroscopy studies.https://www.mdpi.com/1422-0067/23/2/925DNA quadruplexesG-quadruplex CD and fluorescence spectroscopyG-quadruplex structure |
| spellingShingle | Sara Illodo Cibrán Pérez-González Ramiro Barcia Flor Rodríguez-Prieto Wajih Al-Soufi Mercedes Novo Spectroscopic Characterization of Mitochondrial G-Quadruplexes International Journal of Molecular Sciences DNA quadruplexes G-quadruplex CD and fluorescence spectroscopy G-quadruplex structure |
| title | Spectroscopic Characterization of Mitochondrial G-Quadruplexes |
| title_full | Spectroscopic Characterization of Mitochondrial G-Quadruplexes |
| title_fullStr | Spectroscopic Characterization of Mitochondrial G-Quadruplexes |
| title_full_unstemmed | Spectroscopic Characterization of Mitochondrial G-Quadruplexes |
| title_short | Spectroscopic Characterization of Mitochondrial G-Quadruplexes |
| title_sort | spectroscopic characterization of mitochondrial g quadruplexes |
| topic | DNA quadruplexes G-quadruplex CD and fluorescence spectroscopy G-quadruplex structure |
| url | https://www.mdpi.com/1422-0067/23/2/925 |
| work_keys_str_mv | AT saraillodo spectroscopiccharacterizationofmitochondrialgquadruplexes AT cibranperezgonzalez spectroscopiccharacterizationofmitochondrialgquadruplexes AT ramirobarcia spectroscopiccharacterizationofmitochondrialgquadruplexes AT florrodriguezprieto spectroscopiccharacterizationofmitochondrialgquadruplexes AT wajihalsoufi spectroscopiccharacterizationofmitochondrialgquadruplexes AT mercedesnovo spectroscopiccharacterizationofmitochondrialgquadruplexes |