Video Experimental Relacionado
Updated: Jun 3, 2025
14:44
Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR
Published on: December 16, 2013
9.6K
Protección conformal de la nitrogenasa de molibdeno por la proteína Shethna II
Philipp Franke1, Simon Freiberger1, Lin Zhang1
1Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Freiburg im Breisgau, Germany.
Nature
|January 8, 2025
Resumen
Azotobacter vinelandii nitrogenase se protege del daño por oxígeno formando un complejo con la proteína FeSII. Este complejo reversible inactiva la enzima hasta que se agota el oxígeno, asegurando la función de la nitrogenasa.
Área de la Ciencia:
- La bioquímica
- Biología estructural
- Microbiología
Sus antecedentes:
- La nitrogenasa, esencial para la fijación del nitrógeno, es muy sensible al oxígeno.
- Azotobacter vinelandii emplea un mecanismo de protección que involucra a la ferredoxina FeSII (proteína Shethna II) para proteger a la nitrogenasa del daño oxidativo.
- El FeSII actúa como un sensor de oxígeno, que se une a los componentes de la nitrogenasa tras la oxidación de su grupo [2Fe:2S].
Objetivo del estudio:
- Determinar la estructura tridimensional del complejo ternario protector formado entre la Mo-nitrogenasa, su reductasa y el FeSII.
- Elucidar el mecanismo de protección del oxígeno para la nitrogenasa en Azotobacter vinelandii.
Principales métodos:
- Se utilizó la criomicroscopia de partícula única para determinar la estructura del complejo.
- Análisis bioquímico de la formación y disociación de complejos.
Principales resultados:
- El estudio informa la estructura 3D del complejo ternario protector, revelando un complejo de núcleo de 620 kDa que polimeriza en estructuras filamentosas.
- El FeSII se asocia con dos copias de cada componente nitrogenasa, formando un complejo inactivo.
- La formación del complejo se inicia mediante la unión de FeSII al componente de proteína Fe sensible al oxígeno bajo estrés oxidativo.
Conclusiones:
- La proteína FeSII proporciona un mecanismo de "apagado" reversible para proteger a la nitrogenasa del oxígeno.
- Los conocimientos estructurales sobre este complejo protector podrían ser vitales para la ingeniería y el mantenimiento de la actividad de la nitrogenasa en sistemas recombinantes, como en los cultivos alimentarios.
Más Videos Relacionados
Videos de Conceptos Relacionados
01:25Protein Folding
7.7K
Proteins are chains of amino acids linked together by peptide bonds. Upon synthesis, a protein folds into a three-dimensional conformation, critical to its biological function. Interactions between its constituent amino acids guide protein folding, and hence the protein structure is primarily dependent on its amino acid sequence.
Protein Structure Is Critical to Its Biological Function
Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing...
Protein Structure Is Critical to Its Biological Function
Proteins perform a wide range of biological functions such as catalyzing chemical reactions, providing...
7.7K
03:00Molecular Chaperones and Protein Folding
17.7K
The native conformation of a protein is formed by interactions between the side chains of its constituent amino acids. When the amino acids cannot form these interactions, the protein cannot fold by itself and needs chaperones. Notably, chaperones do not relay any additional information required for the folding of polypeptides; the native conformation of a protein is determined solely by its amino acid sequence. Chaperones catalyze protein folding without being a part of the folded protein.
The...
The...
17.7K
02:04Covalently Linked Protein Regulators
6.8K
Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein....
These groups modify specific amino acids in a protein....
6.8K
02:15Protein and Protein Structure
78.3K
Proteins are one of the most abundant organic molecules in living systems and have the most diverse range of functions of all macromolecules. Proteins may be structural, regulatory, contractile, or protective. They may serve in transport, storage, or membranes; or they may be toxins or enzymes. Their structures, like their functions, vary greatly. They are all, however, amino acid polymers arranged in a linear sequence.
A protein's shape is critical to its function. For example, an enzyme...
A protein's shape is critical to its function. For example, an enzyme...
78.3K
01:15¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
1.1K
The axial and equatorial protons in cyclohexane can be distinguished by performing a variable-temperature NMR experiment. In this process, except for one proton, the remaining eleven protons are replaced by deuterium. The deuterium substitution avoids the possible peak splitting caused by the spin-spin coupling between the adjacent protons. The remaining proton flips between the axial and equatorial positions.
1.1K
00:52¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
807
At room temperature, the chair conformer of cyclohexane undergoes rapid ring flipping between two equivalent chair conformers at a rate of approximately 105 times per second. These two chair conformers are in equilibrium. The rapid ring flipping results in the interconversion of the axial proton to an equatorial proton and an equatorial to the axial proton. Such interconversions are too rapid and cannot be detected on the NMR timescale. Hence, the NMR spectrometer cannot distinguish between the...
807