Video Experimental Relacionado
Updated: Jan 25, 2026
09:55
From Constructs to Crystals – Towards Structure Determination of β-barrel Outer Membrane Proteins
Published on: July 4, 2016
14.0K
Bases estructurales de las compuertas por el transportador de la membrana externa FecAA
Andrew D Ferguson1, Ranjan Chakraborty, Barbara S Smith
1Howard Hughes Medical Institute and Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA.
Science (New York, N.Y.)
|March 2, 2002
Resumen
La absorción de hierro en las bacterias depende de los sistemas sideróforos. Los investigadores determinaron la estructura del receptor FecA de Escherichia coli, revelando cómo la unión al citrato férrico desencadena cambios conformacionales para el transporte del hierro.
Área de la Ciencia:
- Microbiología Microbiología.
- Biología Estructural Biología estructural.
- La bioquímica es la bioquímica.
Sus antecedentes:
- El hierro es esencial para el crecimiento bacteriano, y su adquisición a menudo depende de transportadores sideróforos de alta afinidad.
- El receptor FecA en Escherichia coli es un componente clave del sistema de captación de citrato férrico, una importante vía de adquisición de hierro mediada por sideróforos.
Objetivo del estudio:
- Para aclarar la base estructural de la unión y el transporte de citrato férrico por el receptor de la membrana externa FecA.
- Comprender el mecanismo de los cambios conformacionales inducidos por ligandos y la propagación de la señal en los receptores sideróforos.
Principales métodos:
- Se utilizó la cristalografía de rayos X para determinar la estructura de FecA en complejo con citrato férrico.
- Se realizó un análisis estructural de alta resolución a 2.0 y 2.5 angstroms.
Principales resultados:
- La estructura cristalina revelada FecA comprende tres dominios: el barril, el enchufe y la extensión NH2-terminal.
- La unión de citrato férrico indujo un cambio conformacional, cerrando el bolsillo externo de FecA.
- El dominio del enchufe media la propagación de la señal a través de la membrana externa, indicando la ocupación del receptor.
Conclusiones:
- El estudio proporciona la base estructural para comprender el mecanismo de bloqueo en los receptores de membrana externa dependientes de TonB.
- Se propone un mecanismo para el transporte de sideróforos dependientes de la energía basado en datos compilados y conocimientos estructurales.
Videos de Conceptos Relacionados
01:11Protein Transport to the Outer Chloroplast Membrane
2.3K
Chloroplast outer membrane proteins encoded by the nucleus are synthesized in the cytosol. Soon after synthesis, they bind cytosolic factors such as 14-3-3 protein and the Hsp70 chaperones that keep these precursors in an unfolded state until their translocation.
Two models describe the mechanism of precursor recognition and entry across the outer membrane through the TOC complex. Model 1 suggests the newly synthesized precursor binds to the TOC receptor 159 and forms a complex.
Two models describe the mechanism of precursor recognition and entry across the outer membrane through the TOC complex. Model 1 suggests the newly synthesized precursor binds to the TOC receptor 159 and forms a complex.
2.3K
01:31Membrane Transporters
17.8K
Transporters are essential membrane transport proteins with functions related to cell nutrition, homeostasis, communication, etc. Approximately 7% of all genes in the human genome code for transporters or transporter-related proteins.
Transporters are mainly composed of alpha-helices, built from bundles of ten or more helices traversing the plasma membrane. The solute-binding sites are located midway, where some of the helices are broken or distorted, making space for the binding site through...
Transporters are mainly composed of alpha-helices, built from bundles of ten or more helices traversing the plasma membrane. The solute-binding sites are located midway, where some of the helices are broken or distorted, making space for the binding site through...
17.8K
01:44The Significance of Membrane Transport
41.2K
The transport of solutes across the cell membrane is essential for metabolic processes, like maintaining cell size and volume, generating the action potential, exchanging nutrients and gases, etc. Membrane transport can be either passive or active. It can be simple diffusion, facilitated, or mediated transport aided by transport proteins such as transporters and channels.
Transporters facilitate either an active or passive movement of solutes. They can allow a single-molecule transport down its...
Transporters facilitate either an active or passive movement of solutes. They can allow a single-molecule transport down its...
41.2K
01:12Porin Insertion in the Outer Mitochondrial Membrane
4.7K
Porins are beta-barrel proteins translocated to the mitochondrial outer membrane through the TOM complex into the intermembrane space. Porin precursors bind TIM chaperones within the intermembrane space and are guided to the Sorting and Assembly Machinery complex or SAM complex on the outer mitochondrial membrane.
Three models describe the assembly of porins by the SAM complex and their insertion into the outer membrane. Model 1 suggests that porins are assembled outside the SAM channel as the...
Three models describe the assembly of porins by the SAM complex and their insertion into the outer membrane. Model 1 suggests that porins are assembled outside the SAM channel as the...
4.7K
01:19Facilitated Transport
147.0K
The chemical and physical properties of plasma membranes cause them to be selectively permeable. Since plasma membranes have both hydrophobic and hydrophilic regions, substances need to be able to transverse both regions. The hydrophobic area of membranes repels substances such as charged ions. Therefore, such substances need special membrane proteins to cross a membrane successfully. In facilitated transport, also known as facilitated diffusion, molecules and ions travel across a...
147.0K
01:24Cellular Membranes and Drug Transport
1.5K
Drugs must traverse multiple biological barriers, such as multi-layered skin, single-layered intestinal epithelium, and the plasma membrane, to reach their target sites within the body. The plasma membrane, a highly structured composite of phospholipids, carbohydrates, and proteins, is the cell's protective boundary, facilitating selective substance exchange.
Phospholipids arrange themselves into a bilayer, with hydrophilic heads oriented outward and hydrophobic tails facing inward.
Phospholipids arrange themselves into a bilayer, with hydrophilic heads oriented outward and hydrophobic tails facing inward.
1.5K