Video Experimental Relacionado
Updated: May 12, 2026
10:10
Neutron Crystallography Data Collection and Processing for Modelling Hydrogen Atoms in Protein Structures
Published on: December 1, 2020
El sitio activo de cobre de las oxigenasas polisacáridas CBM33 es el cobre
Glyn R Hemsworth1, Edward J Taylor, Robbert Q Kim
1Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom.
Journal of the American Chemical Society
|April 2, 2013
Resumen
Las oxigenasas polisacáridas bacterianas (CBM33) utilizan el cobre para estabilizar las enzimas y degradar la celulosa, de manera similar a las enzimas fúngicas GH61. Esta investigación revela los detalles estructurales y espectroscópicos del CBM33 unido al cobre, que ayuda a la producción de biocombustibles a partir de la biomasa.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Enzimología Enzimología.
- Biotecnología La biotecnología es la biotecnología.
Sus antecedentes:
- Las oxigenasas de polisacáridos dependientes del metal, GH61 (hongos) y CBM33 (bacterias), son cruciales para la degradación de la celulosa.
- Estas enzimas ofrecen potencial para convertir la biomasa recalcitrante en biocombustibles.
- Las enzimas fúngicas GH61 presentan un sitio activo único con un ion de cobre mononuclear y una histidina N-terminal metilada.
Objetivo del estudio:
- Para caracterizar estructural y espectroscópicamente las enzimas bacterianas CBM33 unidas al cobre.
- Para dilucidar el sitio de unión del cobre y la coordinación en CBM33.3.
- Para comparar la coordinación del cobre en CBM33 con la del hongo GH61.1.
Principales métodos:
- Espectroscopia de resonancia paramagnética de electrones (EPR) de banda X de Cu(II) -CBM33.3.
- Espectroscopia UV/Vis para observar la coordinación de los ligandos.
- Estudios de fluorescencia/absorción de rayos X en Cu-CBM33 en solución y cristales.
- Cristalografía de rayos X para la determinación de la estructura en 3D.
Principales resultados:
- CBM33 exhibe la unión de cobre de alta afinidad en un sitio mononuclear, mejorando la estabilidad de la enzima.
- La espectroscopia EPR identificó un sitio de cobre tipo 2 mononuclear con coordinación axial distorsionada.
- Se observó la coordinación de azidas, indicada por una banda de absorción UV/Vis a 390 nm.
- Los estudios de rayos X confirmaron la fotorreducción del cobre a Cu (I) y revelaron una ligadura en forma de T por dos histidinas y el extremo N.
Conclusiones:
- Las enzimas bacterianas CBM33 se unen al cobre de manera similar a las enzimas fúngicas GH61.
- El sitio de cobre caracterizado en CBM33 es estructuralmente análogo al de GH61.1.
- Esta similitud estructural proporciona información sobre el mecanismo de degradación de la celulosa por estas metalloenzimas.
Más Videos Relacionados
11:04Ion Mobility-Mass Spectrometry Techniques for Determining the Structure and Mechanisms of Metal Ion Recognition and Redox Activity of Metal Binding Oligopeptides
Published on: September 7, 2019
14:44Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR
Published on: December 16, 2013
Videos de Conceptos Relacionados
01:46The Calvin Benson Cycle
Ribulose 1,5- bisphosphate carboxylase/oxygenase (RuBisCo) is a critical enzyme that catalyzes carbon dioxide assimilation during photosynthesis. However, it is an inefficient enzyme, having an extremely slow catalytic rate. A typical enzyme can process about a thousand molecules per second; however, RuBisCo fixes only around three-carbon dioxides per second. Photosynthetic cells compensate for this slow rate by synthesizing very high amounts of RuBisCo, making it the most abundant single...
01:26Biosynthesis of Polysaccharides
Polysaccharides such as glycogen and starch are synthesized from nucleoside diphosphate sugars, primarily uridine diphosphate glucose (UDPG) and adenosine diphosphate glucose (ADPG). These activated glucose donors act as key intermediates in carbohydrate metabolism and biosynthesis. UDPG primarily involves glycogen synthesis in animals and many bacteria, while ADPG plays a fundamental role in starch synthesis in plants and certain bacteria.UDPG is formed when glucose-1-phosphate reacts with...
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,...
00:49Ligand Binding and Linkage
Allosteric proteins have more than one ligand binding site; the binding of a ligand to any of these sites influences the binding of ligands to the other sites. When a protein is allosteric, its binding sites are called coupled or linked. In the case of enzymes, the site that binds to the substrate is known as the active site and the other site is known as the regulatory site. When a ligand binds to the regulatory site, this leads to conformational changes in the protein that can influence the...
01:24Oligosaccharide Assembly
Protein glycosylation starts in the ER lumen and continues in the Golgi apparatus. Glycosyltransferases catalyze the addition of sugar molecules or glycosylation of proteins. Usually, these enzymes add sugars to the hydroxyl groups of selected serine or threonine residues to form O-linked glycans or the amino groups of asparagine residues to form N-linked glycans. Different positions on the same polypeptide chain can contain differently linked glycans.
Multiple sugar molecules that may or may...
Multiple sugar molecules that may or may...
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...