Video Experimental Relacionado
Updated: May 13, 2026
![Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F55858.jpg&w=3840&q=50)
10:01
Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase
Published on: December 4, 2017
El ligando de segunda esfera impulsado electrostáticamente cambia entre formas de alta y baja energía de
Damián Alvarez-Paggi1, María A Castro, Verónica Tórtora
1Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab. 2, piso 1, C1428EHA-Buenos Aires, Argentina.
Journal of the American Chemical Society
|March 6, 2013
Resumen
El citocromo c (Cyt) exhibe dos conformaciones que influyen en la energía de reorganización de la transferencia de electrones (λ). Las interacciones electrostáticas desencadenan un cambio entre estas formas, crucial para una transferencia eficiente de electrones entre proteínas.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- La biofísica es la biofísica.
- Biología computacional Biología computacional.
Sus antecedentes:
- El citocromo c (Cyt) es una proteína clave de transferencia de electrones.
- Comprender la energía de reorganización de transferencia de electrones (λ) es vital para los procesos biológicos.
- Las interacciones proteína-proteína y proteína-lípido modulan la función de las citocinas.
Objetivo del estudio:
- Para evaluar la reorganización de transferencia de electrones de energía libre (λ) de Cyt en complejos electrostáticos.
- Investigar los cambios conformacionales de Cyt inducidos por interacciones electrostáticas.
- Para aclarar el papel de los residuos de aminoácidos específicos y bucles de proteínas en la modulación de λ.
Principales métodos:
- Voltametría de la película proteica.
- Espectro vibratorio con resolución temporal electroquímico.
- Simulaciones de dinámica molecular.
Principales resultados:
- Se identificaron dos conformaciones Cyt similares a las nativas con distintos valores λ.
- Las interacciones electrostáticas desencadenan un cambio conformacional de λ alto a λ bajo.
- La ruptura de un enlace H M80-Y67 es una característica clave del conmutador conformacional.
- Los bucles flexibles de Ω actúan como transductores de señales electrostáticas.
Conclusiones:
- Las interacciones electrostáticas ajustan la λ de Cyt a través de cambios conformacionales.
- La mutación Y67F elimina este efecto de ajuste fino.
- Es probable que las interacciones de los socios redox naturales utilicen un mecanismo similar para minimizar la energía de reorganización de la transferencia de electrones entre proteínas.
Videos de Conceptos Relacionados
02:58Crystal Field Theory - Octahedral Complexes
Crystal Field Theory
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
03:02Colors and Magnetism
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
01:43Electron Transport Chain: Complex III and IV
During the electron transport chain, electrons from NADH and FADH2 are first transferred to complexes I and II, respectively. These two complexes then transfer the electrons to ubiquinol, which carries them further to complex III. Complex III passes the electrons across the intermembrane space to Cyt c, which carries them further to complex IV. Complex IV donates electrons to oxygen and reduces it to water. As electrons pass through complexes I, III, and IV, the energy released aids the pumping...
02:46Crystal Field Theory - Tetrahedral and Square Planar Complexes
Tetrahedral Complexes
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
Crystal field theory (CFT) is applicable to molecules in geometries other than octahedral. In octahedral complexes, the lobes of the dx2−y2 and dz2 orbitals point directly at the ligands. For tetrahedral complexes, the d orbitals remain in place, but with only four ligands located between the axes. None of the orbitals points directly at the tetrahedral ligands. However, the dx2−y2 and dz2 orbitals (along the Cartesian axes) overlap with the ligands less than the dxy,...
01:30Ligand-Gated Ion Channel Receptor: Gating Mechanism
Ligand-gated ion channels are transmembrane proteins that play a vital role in intercellular communication and functions of the nervous system. They allow the influx of ions across the membrane once the neurotransmitter binds, allowing the subsequent transmission of electrical excitation across the neurons. Other ligand-gated ion channels, like the γ-aminobutyric acid (GABA) receptor, permit anions like chloride into the cells on the binding of the GABA molecule. Their entry into the cell...
02:42Valence Bond Theory
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...