Video Experimental Relacionado
Updated: Jul 17, 2026
14:27
Steady-state, Pre-steady-state, and Single-turnover Kinetic Measurement for DNA Glycosylase Activity
Published on: August 19, 2013
Comportamiento dinámico de los pares de bases de ADN que contienen 8-oxoguanina
Xiaolin Cheng1, Catherine Kelso, Viktor Hornak
1Department of Chemistry, Stony Brook University, Stony Brook, New York 11794, USA.
Journal of the American Chemical Society
|October 6, 2005
Resumen
La oxidación del ADN, específicamente la 8-oxoguanina (8-oxoG), aumenta la flexibilidad del ADN y facilita la extrusión de bases. Los desajustes como 8-oxoG:A sufren transiciones espontáneas de anti-a-syn, lo que influye en la selectividad de las enzimas de reparación del ADN.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- La bioquímica es la bioquímica.
- Biología computacional Biología computacional.
Sus antecedentes:
- Los mecanismos de reparación del ADN son cruciales para mantener la integridad genómica.
- El daño oxidativo del ADN, particularmente la 8-oxoguanina (8-oxoG), es una lesión común.
- La extrusión de bases es un paso clave en el reconocimiento y reparación de daños en el ADN.
Objetivo del estudio:
- Para investigar la dinámica conformacional de los duplexos de ADN que contienen daño oxidativo.
- Para entender cómo el emparejamiento de bases y el contexto de la secuencia afectan la conformación y la extrusión de 8-oxoG.
- Aclarar los mecanismos subyacentes al reconocimiento del ADN dañado por las enzimas reparadoras.
Principales métodos:
- Simulaciones de dinámica molecular sin restricciones de duplexos de ADN de 13 meros.
- Análisis de las fluctuaciones estructurales del ADN, la flexibilidad y las barreras de extrusión de la base.
- Investigación de las geometrías de los pares de bases y las transiciones conformacionales de nucleósidos.
Principales resultados:
- El 8-oxoG en el ADN dúplex exhibe una mayor flexibilidad y una barrera reducida a la extrusión de bases en comparación con la guanina normal.
- El desajuste 8-oxoG:A muestra una importante inestabilidad estructural y sufre transiciones espontáneas anti-syn.
- La sinconformación de 8-oxoG es preferida termodinámicamente, impulsada por factores estéricos y electrostáticos.
- Las vías y las tasas de transición dependen de la secuencia, lo que proporciona información sobre la especificidad de la enzima.
Conclusiones:
- El daño oxidativo altera la dinámica del ADN y las estructuras de equilibrio, facilitando la reparación.
- La flexibilidad conformal y el contexto de la secuencia juegan un papel crítico en el reconocimiento de daños en el ADN.
- Estos hallazgos ofrecen una visión mecanicista de la acción selectiva de las enzimas de reparación del ADN en el ADN dañado.
Más Videos Relacionados
12:15Quantification of three DNA Lesions by Mass Spectrometry and Assessment of Their Levels in Tissues of Mice Exposed to Ambient Fine Particulate Matter
Published on: May 29, 2019
05:13Quantifying the Level of 8-oxo-dG Using ELISA Assay to Evaluate Oxidative DNA Damage in MCF-7 Cells
Published on: May 24, 2024
Videos de Conceptos Relacionados
02:02DNA Topoisomerases
Topoisomerases are enzymes that relax overwound DNA molecules during various cell processes, including DNA replication and transcription. These enzymes regulate positive and negative DNA supercoiling without changing the nucleotide sequence. DNA overwinding in a clockwise direction results in positively supercoiled DNA, whereas underwinding in a counterclockwise direction produces negatively supercoiled DNA.
Types and Mechanism of action
Topoisomerases are divided into two main types. Type I...
Types and Mechanism of action
Topoisomerases are divided into two main types. Type I...
02:25Overview of DNA Repair
In order to be passed through generations, genomic DNA must be undamaged and error-free. However, every day, DNA in a cell undergoes several thousand to a million damaging events by natural causes and external factors. Ionizing radiation such as UV rays, free radicals produced during cellular respiration, and hydrolytic damage from metabolic reactions can alter the structure of DNA. Damages caused include single-base alteration, base dimerization, chain breaks, and cross-linkage.
Chemically...
Chemically...
02:36DNA Damage can Stall the Cell Cycle
In response to DNA damage, cells can pause the cell cycle to assess and repair the breaks. However, the cell must check the DNA at certain critical stages during the cell cycle. If the cell cycle pauses before DNA replication, the cells will contain twice the amount of DNA. On the other hand, if cells arrest after DNA replication but before mitosis, they will contain four times the normal amount of DNA. With a host of specialized proteins at their disposal,cells must use the right protein at...
02:25Overview of DNA Repair
In order to be passed through generations, genomic DNA must be undamaged and error-free. However, every day, DNA in a cell undergoes several thousand to a million damaging events by natural causes and external factors. Ionizing radiation such as UV rays, free radicals produced during cellular respiration, and hydrolytic damage from metabolic reactions can alter the structure of DNA. Damages caused include single-base alteration, base dimerization, chain breaks, and cross-linkage.
Chemically...
Chemically...
02:36DNA Damage Can Stall the Cell Cycle
In response to DNA damage, cells can pause the cell cycle to assess and repair the breaks. However, the cell must check the DNA at certain critical stages during the cell cycle. If the cell cycle pauses before DNA replication, the cells will contain twice the amount of DNA. On the other hand, if cells arrest after DNA replication but before mitosis, they will contain four times the normal amount of DNA. With a host of specialized proteins at their disposal,cells must use the right protein at...
01:30Spontaneous and Induced Mutations
Spontaneous mutations arise infrequently during DNA replication due to errors in the process. A key factor behind these errors is tautomeric shifts in nitrogenous bases, where bases transition from keto to enol forms or amino to imino forms. This shift can alter base-pairing rules, leading to mutations. Additionally, reactive oxygen species (ROS) arising from aerobic metabolism can damage DNA, resulting in depurination (loss of a purine base) or depyrimidination (loss of a pyrimidine base).