Video Experimental Relacionado
Updated: Mar 19, 2026
09:27
Functional Complementation Analysis FCA: A Laboratory Exercise Designed and Implemented to Supplement the Teaching of Biochemical Pathways
Published on: June 24, 2016
18.3K
Activación dependiente del ribosoma de un control estricto
Alan Brown1, Israel S Fernández1, Yuliya Gordiyenko1
1MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
Nature
|June 10, 2016
Resumen
La supervivencia de las bacterias depende de la sensación de estrés. Los investigadores revelaron estructuralmente cómo la enzima RelA se une a los ribosomas estancados para desencadenar la respuesta estricta, un mecanismo clave de supervivencia, que ofrece nuevos objetivos de fármacos antibacterianos.
Área de la Ciencia:
- Microbiología
- Biología molecular
- Biología estructural
Sus antecedentes:
- Las bacterias se adaptan a los cambios ambientales a través de respuestas al estrés.
- El control estricto, desencadenado por el hambre de nutrientes, reprograma el metabolismo bacteriano y la expresión génica para la supervivencia.
- La alarmona (p) ppGpp, sintetizada por RelA, es fundamental para esta respuesta.
Objetivo del estudio:
- Para aclarar el mecanismo estructural de la unión de RelA a los ribosomas bacterianos estancados.
- Comprender cómo RelA distingue los tRNA sin carga de los aminoacilados.
- Proporcionar una base estructural para la orientación de RelA en el desarrollo de fármacos antibacterianos.
Principales métodos:
- Se utilizó la crio-microscopía electrónica (cryo-EM) para determinar la estructura de RelA unido a los ribosomas bacterianos.
- Se utilizaron ensayos bioquímicos para validar los hallazgos estructurales.
Principales resultados:
- La estructura cryo-EM revela el sitio de unión único de RelA en los ribosomas estancados, distinto de otros factores de traducción.
- La arquitectura de múltiples dominios de RelA interactúa con un tRNA de sitio A distorsionado.
- El dominio TGS de RelA impide estéricamente la unión al tRNA aminoacilado, facilitando la síntesis de (p) pGpp.
Conclusiones:
- La estructura explica la activación de RelA por ribosomas estancados y su discriminación contra los tRNA cargados.
- Este mecanismo inicia la respuesta estricta, crucial para la supervivencia bacteriana bajo estrés.
- RelA es un objetivo prometedor para el desarrollo de nuevas terapias contra bacterias patógenas.
Videos de Conceptos Relacionados
01:23Stringent Response in E. coli
457
Bacterial growth is closely tied to nutrient availability, with cells proliferating exponentially under favorable conditions and entering a stationary phase when resources become scarce. This transition is mediated by a regulatory mechanism known as the stringent response, which allows bacteria to adapt to nutrient deprivation by modulating gene expression and metabolic activity.During nutrient scarcity, intracellular amino acid levels decline. It results in the accumulation of uncharged tRNAs...
457
01:31Regulation of the Unfolded Protein Response
3.2K
Inositol-requiring kinase one or IRE1 is the most conserved eukaryotic unfolded protein response (UPR) receptor. It is a type I transmembrane protein kinase receptor with a distinctive site-specific RNase activity. As the binding mechanics of the misfolded proteins with the N-terminal domain of IRE-1 are unclear, three binding models — direct, indirect, and allosteric -- are proposed for receptor activation. Nevertheless, it is known that once a misfolded protein associates with IRE1, it...
3.2K
01:30Other Stress Responses in Bacteria
500
Bacteria have global regulatory systems that control several types of stress mechanisms. These include Pho regulon and the heat shock response, which are essential systems for environmental adaptation, such as nutrient limitation and proteotoxic stress. The Pho regulon and the heat shock response exemplify bacterial resilience, enabling rapid adaptation to fluctuating environmental conditions.Pho RegulonBacteria require phosphorus for essential cellular processes, including nucleic acid...
500
01:29Translational Regulation
766
Translational regulation in prokaryotes ensures efficient protein synthesis by controlling ribosome access to mRNA. This regulation is mediated by secondary RNA structures, including translational riboswitches, RNA thermometers, and small RNAs (sRNAs), which respond to intracellular and environmental signals to modulate gene expression.Translational RiboswitchesRiboswitches in the leader region of mRNAs can regulate translation by altering the accessibility of the Shine-Dalgarno (SD) sequence,...
766
01:28Global Regulatory Systems
845
Global regulatory systems in bacteria enable rapid and coordinated responses to environmental changes by integrating sensory inputs with gene expression, ensuring efficient adaptation to fluctuating conditions. Key global regulatory mechanisms include regulons, two-component systems, sigma factors, and secondary messengers.Regulons and Global RegulatorsA regulon is a collection of genes and operons controlled by a common global regulator. These regulators enable bacteria to prioritize resource...
845
01:34Directing Proteins to the Rough Endoplasmic Reticulum
18.3K
The organelle-specific signaling sequences direct proteins synthesized in the cytosol to their final destination like ER, mitochondria, peroxisomes, etc. Some of the proteins directed to ER are then trafficked via vesicles to other organelles within the cell or the extracellular environment through the Golgi complex. For example, the rough ER synthesizes soluble proteins for transportation to the lysosomes or secretion out of the cell. It can also synthesize transmembrane proteins that can...
18.3K