Video Experimental Relacionado
Updated: Jul 10, 2026
10:26
Biotinylated Cell-penetrating Peptides to Study Intracellular Protein-protein Interactions
Published on: December 20, 2017
Catalizando la translocación de polipéptidos a través de interacciones atractivas
Aaron J Wolfe1, Mohammad M Mohammad, Stephen Cheley
1Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA.
Journal of the American Chemical Society
|October 24, 2007
Resumen
Los poros de proteínas diseñados con sitios de unión específicos pueden controlar la cinética de translocación de polipéptidos. La introducción de sitios de unión electrostática redujo significativamente las barreras de energía de translocación para las moléculas cargadas.
Área de la Ciencia:
- La biofísica es la biofísica.
- Ingeniería de proteínas Ingeniería de proteínas.
- Biología Molecular Biología Molecular
Sus antecedentes:
- La translocación de polipéptidos a través de los poros de las proteínas es esencial en biología.
- Comprender cómo los sitios de unión afectan la cinética de la translocación es crucial, pero falta.
- La alfa-hemolisina estafilocócica (alphaHL) es un sistema de poros de proteínas bien caracterizado.
Objetivo del estudio:
- Investigar los mecanismos cinéticos de la translocación de polipéptidos a través de poros alfaHL diseñados.
- Para aclarar cómo las modificaciones específicas del sitio de unión alteran la dinámica de translocación.
- Para cuantificar el impacto de las interacciones electrostáticas en la eficiencia de la translocación.
Principales métodos:
- Diseño racional de proteínas para diseñar sitios de unión dentro del poro alphaHL.
- Grabaciones eléctricas de un solo canal para monitorear eventos de translocación de polipéptidos.
- Análisis cinético para determinar constantes de velocidad y barreras de energía libre.
Principales resultados:
- Los sitios de unión ácida diseñados facilitaron la translocación de los polipéptidos catiónicos.
- La introducción de dos sitios de unión electrostática aumentó las tasas de asociación y disociación.
- Los polipéptidos hidrofóbicos mostraron tasas de asociación disminuidas debido a la naturaleza hidrofílica del poro.
Conclusiones:
- La ingeniería específica del sitio de unión en los poros de las proteínas puede controlar con precisión la cinética de la translocación.
- Las interacciones electrostáticas dentro de la luz de los poros reducen significativamente las barreras de energía para el transporte de moléculas cargadas.
- El entorno interno del poro dicta la eficiencia de la translocación basada en la hidrofobidad del polipéptido.
Videos de Conceptos Relacionados
01:20Cotranslational Protein Translocation
Translocation of proteins across membranes is an ancient process that occurs even in bacteria and archaebacteria. In fact, the components of the translocation machinery are still conserved between prokaryotes and eukaryotes.
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
01:27Post-translational Translocation of Proteins to the RER
A sizable fraction of proteins destined for ER are first synthesized in the cell cytosol and then transported across the ER membrane–a process called post-translational translocation. Similar to cotranslationally translocated proteins, these proteins also use the Sec translocon complex to enter the ER lumen.
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
Targeting proteins to the ER
Hsp40 and Hsp70 chaperone molecules bind the translated proteins in the cytosol to prevent their folding. The chaperone binding helps to keep the signal...
01:37Energy to Drive Translocation
Mitochondrial protein import is powered by two distinct energy sources: ATP hydrolysis and electrochemical potential across the inner membrane. Newly synthesized precursors are bound by cytosolic chaperones of the Hsp70 family, which guide them to the import receptors on the mitochondrial surface. Utilizing the energy of ATP hydrolysis, Hsp70 chaperones transfer these precursors to the TOM receptors on the mitochondrial outer membrane.
Generally, polypeptides are unfolded by two distinct...
Generally, polypeptides are unfolded by two distinct...
01:28Protein Translocation Machinery on the ER Membrane
The translocon complex situated on the ER membrane is the main gateway for the protein secretory pathway. It facilitates the transport of nascent peptides into the ER lumen and their insertion into the ER membrane.
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the translocon complex.
Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the translocon complex.
01:45Overview of Protein Sorting and Transport
Eukaryotic cells have different membrane-bound organelles with distinct protein requirements. The process by which proteins are targeted to a specific organelle is called protein sorting.
Protein sorting can be of two types: signal-based sorting and vesicle-based trafficking. In signal-based sorting, specific amino acid sequences called sorting signals target proteins to the proper location inside the cell either via gated transport or by protein translocation. In gated transport, folded...
Protein sorting can be of two types: signal-based sorting and vesicle-based trafficking. In signal-based sorting, specific amino acid sequences called sorting signals target proteins to the proper location inside the cell either via gated transport or by protein translocation. In gated transport, folded...
01:26Bacterial Translocation and Protein Secretion
Bacterial protein secretion involves translocation systems to ensure proteins reach their designated locations, including the plasma membrane, periplasm, outer membrane, or the external environment. These translocation systems are vital for bacterial physiology, supporting processes like membrane assembly, enzymatic activity in the periplasm, and interactions with the external environment. The division of labor between Sec and Tat pathways ensures efficiency in handling proteins with diverse...