Video Experimental Relacionado

Updated: Jul 7, 2026

Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR

Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D ¹H NMR

Published on: December 16, 2013

La estructura del sitio activo de la umecianina, la estelacianina de las raíces de rábano picante

Christopher Dennison¹, Mark D Harrison

¹School of Natural Sciences, Bedson Building, University of Newcastle upon Tyne, Newcastle upon Tyne, NE1 7RU, UK. christopher.dennison@ncl.ac.uk

Journal of the American Chemical Society

|February 26, 2004

Resumen

Este estudio utilizó RMN paramagnética para analizar la umecianina, una proteína de cobre. Los resultados muestran que tiene un típico sitio de cobre tipo 1, con el ligando de glutamina axial coordinado a través de su oxígeno amida.

Área de la Ciencia:

La bioquímica es la bioquímica.
Química bioorgánica Química bioorgánica.
Biología Estructural Biología estructural.

Sus antecedentes:

Las cupredoxinas presentan sitios de cobre tipo 1 con ligandos ecuatoriales His(2)Cys y un Met axial, lo que generalmente resulta en una geometría tetraédrica distorsionada.
La umecianina (UMC) es una variante de la estelacianina con un ligando axial de glutamina (Gln), que difiere del ligando común de metionina (Met).

Objetivo del estudio:

Para investigar la estructura del sitio activo de la umecianina (UMC), específicamente el entorno de coordinación de su sitio de cobre tipo 1.
Determinar el modo de coordinación del ligando Gln axial en UMC utilizando espectroscopia de RMN paramagnética.
Para comparar la estructura del sitio activo de UMC con otras cupredoxinas y comprender la influencia de las variaciones estructurales.

Principales métodos:

Se empleó la espectroscopia de RMN paramagnética (1) H para estudiar los derivados de cobre (II) y níquel (II) de la umecianina ([Ni (II) UMC]).
Se realizaron asignaciones espectrales para identificar y analizar las resonancias de los ligandos del sitio activo.
Se investigó la influencia de la transición alcalina en la estructura de la proteína y la coordinación de los ligandos.

Principales resultados:

Los espectros de RMN asignados confirmaron un conjunto de coordinación ecuatorial de His(2) Cys para Cu(II) UMC, consistente con los sitios típicos de cobre tipo 1.
No se observaron resonancias paramagnéticamente desplazadas del ligando axial en Cu(II) UMC, lo que indica que no interactúa significativamente con el orbital molecular ocupado individualmente (SOMO).
La RMN paramagnética de Ni ((II) UMC reveló que el ligando Gln axial coordina monodentalmente a través de su átomo de oxígeno amida de la cadena lateral.
La transición alcalina afectó a los residuos ligantes pero no alteró el modo de coordinación del ligando Gln.

Conclusiones:

La umecianina posee un sitio de cobre tipo 1 clásico, a pesar de las variaciones en su ligando axial en comparación con otras estelacianinas.
El ligando Gln axial en UMC se coordina a través de su oxígeno amida y no influye significativamente en la estructura electrónica del centro de cobre.
Las diferencias estructurales en UMC en comparación con otras estelacianinas no alteran sustancialmente las características espectrales paramagnéticas de RMN de su sitio de cobre tipo 1.

Más Videos Relacionados

MALDI-Mass Spectrometric Imaging for the Investigation of Metabolites in Medicago truncatula Root Nodules

MALDI-Mass Spectrometric Imaging for the Investigation of Metabolites in Medicago truncatula Root Nodules

Published on: March 5, 2014

Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry

Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry

Published on: October 18, 2019

Videos de Conceptos Relacionados

Atomic Structure

Atomic Structure

All matter is composed of atoms, the smallest individual units of elements. Each atom is made up of three subatomic particles: protons, neutrons, and electrons. Together, these three particles account for the mass and the charge of an atom.The History of Atomic TheoryThe first person to propose that everything on Earth is made up of tiny particles was the Greek philosopher Democritus, around 450 B.C. He used the term atomos, Greek for “indivisible,” from which the modern term “atom” is derived.

Nuclear Stability

Nuclear Stability

Protons and neutrons, collectively called nucleons, are packed together tightly in a nucleus. With a radius of about 10−15 meters, a nucleus is quite small compared to the radius of the entire atom, which is about 10−10 meters. Nuclei are extremely dense compared to bulk matter, averaging 1.8 × 1014 grams per cubic centimeter. If the earth’s density were equal to the average nuclear density, the earth’s radius would be only about 200 meters.
To hold positively charged protons together in the...

Structure of Benzene: Molecular Orbital Model

Structure of Benzene: Molecular Orbital Model

According to the molecular orbital (MO) model, benzene has a planar structure with a regular hexagon of six sp2 hybridized carbons. As shown in Figure 1, each carbon is bonded to three other atoms with C–C–C and H–C–C bond angles of 120°. The C–H bond length is 109 pm, and the C–C bond length is 139 pm which is midway between the single bond length of sp3 hybridized carbons (154 pm) and sp2 hybridized carbons (133 pm).

Structure of Amines

Structure of Amines

The hybridized nitrogen atom in amines possesses a lone pair of electrons and is bound to three substituents with a bond angle of around 108°, which is less than the tetrahedral angle of 109.5°. However, the C–N–H bond angle is slightly larger at 112°, with a carbon–nitrogen bond length of 147 pm. This carbon–nitrogen bond length of of amines is longer than the carbon–oxygen bond of alcohols (143 pm) but shorter than alkanes’ carbon–carbon bond (154 pm). These aspects are illustrated in Figure...

Atomic Nuclei: Nuclear Spin

Atomic Nuclei: Nuclear Spin

All atomic particles possess an intrinsic angular momentum, or 'spin'. Electrons, protons, and neutrons each have a spin value of ½, although protons and neutrons in nuclei may have higher half-integer spins owing to energetic factors.
Atomic nuclei have a net nuclear spin, , which can have an integer or half-integer value. In atomic nuclei, the spins of protons are paired against each other but not with neutrons, and vice versa. Consequently, an even number of protons does not contribute to...

Atomic Nuclei: Nuclear Magnetic Moment

Atomic Nuclei: Nuclear Magnetic Moment

All atomic nuclei are positively charged. When they have a nonzero spin, they behave like rotating charges. As a consequence of their charge and spin, these nuclei generate a magnetic field (B). This, in turn, gives rise to a magnetic moment (μ), which is randomly oriented in the absence of an external magnetic field. When an external magnetic field (B0) is applied, the magnetic moment vectors can align with the field or against it in 2 + 1 orientations. A hydrogen nucleus, which is just a...