Video Experimental Relacionado
Updated: Jul 19, 2026
09:42
Unraveling Entropic Rate Acceleration Induced by Solvent Dynamics in Membrane Enzymes
Published on: January 16, 2016
Análisis mecanicista del intercambio de dominio de la aciltransferasa en módulos de poliquetida sintasa
Marcus Hans1, Andreas Hornung, Agnieszka Dziarnowski
1Department of Chemical Engineering, Stanford University, Stanford, California 94306, USA.
Journal of the American Chemical Society
|May 2, 2003
Resumen
La alteración de las poliquetidas sintasas (PKSs) mediante el intercambio de dominios reduce la formación de productos. Este estudio revela que el alargamiento de la cadena alterado por la cetosintasa y los dominios ACP, no la especificidad alterada del sustrato, es la causa principal.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Molecular Biología Molecular
- Enzimología Enzimología.
Sus antecedentes:
- Las sintasas modulares de policetido tipo I (PKS) sintetizan muchos policetidos.
- La sustitución de dominios en las PKS puede alterar las estructuras poliquetídicas, pero a menudo reduce la formación de productos.
- La base molecular para la eficiencia reducida en los módulos PKS híbridos no está clara.
Objetivo del estudio:
- Analizar sistemáticamente el impacto del intercambio de dominio de la aciltransferasa (AT) en la 6-deoxyeritronolide B sintasa (DEBS) en la función del módulo PKS.
- Para aclarar la base molecular para la formación de productos reducidos en módulos PKS híbridos.
Principales métodos:
- Análisis cinético sistemático de módulos híbridos DEBS con dominios AT intercambiados.
- Analiza la formación de acil-AT, la actividad de la aciltransferasa acil-CoA:ACP y la condensación catalizada por la cetosintasa.
- Estudios de rotación única y proteólisis limitada para sondear la función y estructura de la enzima.
Principales resultados:
- Los módulos híbridos mostraron una disminución de 15 a 20 veces en la facturación en comparación con los DEBS de tipo salvaje.
- Los dominios heterólogos de AT mantuvieron su actividad y especificidad.
- El alargamiento de la cadena por los dominios de la cetosintasa (KS) y la proteína portadora de acilo (ACP) se atenuó significativamente en los módulos híbridos.
Conclusiones:
- El defecto principal en los módulos PKS híbridos no es la especificidad del dominio AT alterada, sino el alargamiento de la cadena afectado por los dominios KS y ACP.
- Las diferencias estructurales, particularmente entre los dominios KR y ACP, pueden explicar la reducción de la eficiencia catalítica.
Videos de Conceptos Relacionados
01:58Cooperative Allosteric Transitions
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
01:58Mechanical Protein Functions
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.
01:58Cooperative Allosteric Transitions
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
01:19Allosteric Proteins-ATCase
Binding sites linkages can regulate a protein's function. For example, enzyme activity is often regulated through a feedback mechanism where the end product of the biochemical process serves as an inhibitor.
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
01:58Cooperative Allosteric Transitions
Cooperative allosteric transitions can occur in multimeric proteins, where each subunit of the protein has its own ligand-binding site. When a ligand binds to any of these subunits, it triggers a conformational change that affects the binding sites in the other subunits; this can change the affinity of the other sites for their respective ligands. The ability of the protein to change the shape of its binding site is attributed to the presence of a mix of flexible and stable segments in the...
01:58Mechanical Protein Function
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.