Video Experimental Relacionado
Updated: Jul 13, 2026

12:08
Diagonal Method to Measure Synergy Among Any Number of Drugs
Published on: June 21, 2018
La torsión del ADN y los efectos de las bases no contactadas en la afinidad del operador 434 para el represor 434
1Department of Biological Sciences, State University of New York, Buffalo 14260.
Nature
|January 2, 1992
Resumen
La afinidad de unión del represor del bacteriófago 434 está influenciada por el ADN del ADN.
Área de la Ciencia:
- Biología Molecular Biología Molecular
- Biología Estructural Biología estructural.
- Genética La genética.
Sus antecedentes:
- El represor del bacteriófago 434 controla la expresión génica a través de la unión del operador.
- Los sitios de los operadores exhiben regiones exteriores conservadas y bases centrales divergentes.
- Las bases centrales, aunque no están directamente en contacto, afectan la afinidad de unión del represor.
Objetivo del estudio:
- Para investigar la relación entre la torsión intrínseca del ADN y la afinidad de unión del represor.
- Para dilucidar el papel de la secuencia de ADN en la modulación de la función del operador.
Principales métodos:
- Análisis de secuencias de operadores de ADN y sus pares de bases centrales.
- Medición de las afinidades de unión entre el represor y el operador.
- Evaluación de la torsión y flexibilidad del ADN utilizando técnicas biofísicas.
Principales resultados:
- Existe una correlación entre la torsión intrínseca del ADN de un operador y su afinidad de unión al represor.
- Los operadores con menor afinidad exhiben un ADN menos retorcido en comparación con los operadores de mayor afinidad.
- La unión del represor normaliza la torsión de los operadores de alta y baja afinidad.
Conclusiones:
- La torsión intrínseca del ADN y la flexibilidad de la torsión del ADN son factores críticos en las interacciones del represor-operador del bacteriófago 434.
- Estas propiedades estructurales del ADN influyen en la discriminación del represor entre los sitios del operador.
Videos de Conceptos Relacionados
Types of RNA
Overview
Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs perform diverse functions and can be broadly classified as protein-coding or non-coding RNA. Non-coding RNAs play important roles in the regulation of gene expression in response to developmental and environmental changes. Non-coding RNAs in prokaryotes can be manipulated to develop more effective antibacterial drugs for human or animal use.
RNA...
Three main types of RNA are involved in protein synthesis: messenger RNA (mRNA), transfer RNA (tRNA), and ribosomal RNA (rRNA). These RNAs perform diverse functions and can be broadly classified as protein-coding or non-coding RNA. Non-coding RNAs play important roles in the regulation of gene expression in response to developmental and environmental changes. Non-coding RNAs in prokaryotes can be manipulated to develop more effective antibacterial drugs for human or animal use.
RNA...
Drug-Receptor Bonds
Drug-receptor bonds are formed through various chemical forces when drugs interact with target cells. Covalent bonds, strong and irreversible, are exemplified by DNA-alkylating anticancer agents that inhibit cell division. However, such irreversible drug binding lacks selectivity and can modify the DNA of the surrounding healthy cells. Covalent binding often contributes to tissue toxicity, as seen with chloroform and paracetamol metabolites binding to the liver, causing hepatotoxicity.
In...
In...
Combined Effects of Drugs: Antagonism
The combined effects of drugs can result in various interactions, of which an important type is antagonism. Antagonism is a mechanism where one drug inhibits or counteracts the effects of another drug. Antagonism can occur through various means, including receptor binding, allosteric modulation, functional interaction, chemical reactions, and pharmacokinetic processes.
The most common type is receptor antagonism, where one drug acts as an antagonist to block the effects of another drug by...
The most common type is receptor antagonism, where one drug acts as an antagonist to block the effects of another drug by...
Combined Effects of Drugs: Synergism
Synergism is a useful mechanism where combining two or more drugs is more effective than each constituent used alone. Such combinations are also called supra-additive interactions. The drugs collectively enhance the final therapeutic effect by acting on different targets. Another advantage is that the low dose of each constituent drug is sufficient to achieve the desired effect. This helps reduce the duration of therapy and lower the adverse effects of these drugs.
Such synergistic combinations...
Such synergistic combinations...
Inhibitors of Bacterial Protein Synthesis
Aminoglycosides constitute a highly potent class of bactericidal antibiotics that exert their antimicrobial effects by targeting the bacterial ribosome, specifically disrupting protein synthesis. These polycationic molecules consist of amino-modified sugars linked via glycosidic bonds to an aminocyclitol core such as 2-deoxystreptamine or streptamine. Their strong positive charges facilitate tight binding to the negatively charged phosphate backbone of ribosomal RNA (rRNA), primarily at the 16S...
Inhibitors of Bacterial DNA Synthesis
Bacterial pathogens depend on precise and efficient DNA replication to sustain infection. Two type II topoisomerases—DNA gyrase and topoisomerase IV—are critical to this process, as they resolve DNA supercoiling and unlink chromosomes during replication. Fluoroquinolones, synthetic derivatives of quinolones, exploit this mechanism by stabilizing the transient DNA–enzyme cleavage complex, preventing strand religation, and causing lethal double-strand breaks. These antibiotics are selectively...

