Video Experimental Relacionado
Updated: Feb 13, 2026
07:37
Single-Molecule Real-Time Visualization of DNA Unwinding by CMG Helicase
Published on: September 27, 2024
2.5K
El mecanismo de activación de la CMG helicasa en los eucariotas
Max E Douglas1, Ferdos Abid Ali2, Alessandro Costa2
1Chromosome Replication Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK.
Nature
|March 1, 2018
Resumen
El inicio de la replicación del ADN eucariota implica dos etapas. Los factores de disparo activan el complejo de mantenimiento del minicromosoma (MCM) en dos helicasas Cdc45-MCM-GINS (CMG), asegurando una replicación precisa del ADN.
Área de la Ciencia:
- Biología molecular
- La bioquímica
- La genética
Sus antecedentes:
- La replicación del ADN eucariota se inicia en dos etapas: ensamblaje del complejo MCM y activación mediada por el factor de disparo.
- El complejo MCM forma un hexámero doble alrededor del ADN de origen durante la fase G1.
- Los factores de disparo convierten el hexámero doble MCM en dos helicasas activas CMG durante la fase S.
Objetivo del estudio:
- Para aclarar el mecanismo de la activación de la helicasa replicativa en eucariotas.
- Detallar las funciones de la unión y la hidrólisis de ADP/ATP en el ensamblaje y la activación de la CMG helicasa.
- Comprender el proceso de translocación de la helicasa de CMG y sus implicaciones para el establecimiento de replicomas.
Principales métodos:
- Ensayos bioquímicos para estudiar las interacciones entre el complejo MCM y los factores de disparo.
- Análisis de la unión de nucleótidos (ADP/ATP) y la hidrólisis.
- Experimentos in vitro para controlar el desenrollo del ADN y la activación de la helicasa.
- Investigando el papel de Mcm10 en la activación de la helicasa.
Principales resultados:
- El complejo MCM permanece unido a ADP después de la formación de doble hexámero.
- Los factores de disparo desencadenan la liberación de ADP, y la unión de ATP promueve el ensamblaje estable de CMG.
- El ensamblaje de CMG implica el desenroscamiento del ADN y la separación del doble hexámero en dos helicasas inactivas.
- Mcm10 y la hidrólisis de ATP desvían aún más el ADN y activan las helicasas.
- Las helicasas activadas de CMG se translocan en una dirección N-terminal-primera, pasando unas por otras.
Conclusiones:
- El estudio revela un mecanismo detallado para la activación de la helicasa replicativa eucariota.
- La liberación de ADP y la unión de ATP son críticas para el ensamblaje y la activación de CMG.
- El mecanismo de translocación N-terminal-primero asegura el establecimiento eficiente del replicoma.
- Este proceso proporciona un mecanismo de seguridad para la replicación bidireccional del ADN.
Más Videos Relacionados
10:11Author Spotlight: Investigating the Motion Dynamics of the Eukaryotic Replisome Components at the Single-Molecule Level
Published on: July 26, 2024
1.7K
09:09High Throughput, Real-time, Dual-readout Testing of Intracellular Antimicrobial Activity and Eukaryotic Cell Cytotoxicity
Published on: November 16, 2016
8.4K
Videos de Conceptos Relacionados
00:55DNA Helicases
24.2K
DNA unwinding helicase enzymes are a type of motor protein. Motor proteins can translocate along filaments or polymers using energy generated from ATP hydrolysis. Helicases are involved in all the important cellular processes where DNA unwinding is required, such as DNA replication, repair, recombination, and transcription. They are present in all living organisms, but vary in their structure, function, and mechanism of action. For example, in prokaryotes, DnaB helicase binds and translocates...
24.2K
02:31Replication in Eukaryotes
205.9K
Overview
205.9K
02:42Eukaryotic Transcription Activators
12.9K
Transcription activators are proteins that promote the transcription of genes from DNA to RNA. In most cases, these proteins contain two separate domains ‒ a domain that binds to DNA and a domain for activating transcription; however, in some cases, a single domain is responsible for both binding and activation of transcription, as seen in the glucocorticoid receptor and MyoD.
The binding domains are capable of recognizing and interacting with regulatory sequences on the DNA. These...
The binding domains are capable of recognizing and interacting with regulatory sequences on the DNA. These...
12.9K
00:58Eukaryotic RNA Polymerases
27.2K
RNA Polymerase (RNAP) is conserved in all animals, with bacterial, archaeal, and eukaryotic RNAPs sharing significant sequence, structural, and functional similarities. Among the three eukaryotic RNAPs, RNA Polymerase II is most similar to bacterial RNAP in terms of both structural organization and folding topologies of the enzyme subunits. However, these similarities are not reflected in their mechanism of action.
All three eukaryotic RNAPs require specific transcription factors, of which the...
All three eukaryotic RNAPs require specific transcription factors, of which the...
27.2K
02:40The Eukaryotic Promoter Region
19.0K
The eukaryotic promoter region is a segment of DNA located upstream of a gene. It contains an RNA polymerase binding site, a transcription start site, and several cis-regulatory sequences. The proximal promoter region is located in the vicinity of the gene and has cis-regulatory sequences and the core promoter. The core promoter is the binding site for RNA polymerase and is usually located between -35 and +35 nucleotides from the transcription start site. The distal promoter regions are...
19.0K
01:58Mechanical Protein Functions
5.7K
Proteins perform many mechanical functions in a cell. These proteins can be classified into two general categories- proteins that generate mechanical forces and proteins that are subjected to mechanical forces. Proteins providing mechanical support to the structure of the cell, such as keratin, are subjected to mechanical force, whereas proteins involved in cell movement and transport of molecules across cell membranes, such as an ion pump, are examples of generating mechanical force.
5.7K