Search research articles

ACERCA DE JoVE

Visión General Liderazgo Blog Centro de Ayuda JoVE

AUTORES

Proceso de Publicación Consejo Editorial Alcance y Políticas Revisión por Pares Preguntas Frecuentes Enviar

BIBLIOTECARIOS

Testimonios Suscripciones Acceso Recursos Consejo Asesor de Bibliotecas Preguntas Frecuentes

INVESTIGACIÓN

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archivo

EDUCACIÓN

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Centro de Recursos para Profesores Sitio de Profesores

Términos y Condiciones de Uso

Política de Privacidad

Videos de Conceptos Relacionados

Mechanical Protein Functions

Mechanical 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.

SN1 Reaction: Stereochemistry

S_N1 Reaction: Stereochemistry

This lesson provides an in-depth discussion of the stereochemical outcomes in an SN1 reaction.
In the first step of an SN1 reaction, the bond between the electrophilic carbon and the leaving group ionizes to generate the carbocation intermediate. The second step of the mechanism is the nucleophilic attack.
In the formed carbocation, the positively charged carbon is sp2 hybridized with a trigonal planar geometry. As all the three substituents lie on the same plane, a plane of symmetry for the...

SN1 Reaction: Kinetics

S_N1 Reaction: Kinetics

In an SN2 reaction, the reaction rate depends on both the type of nucleophile and the substrate. A hindered tertiary alkyl halide is practically inert to the SN2 mechanism despite using a strong nucleophile.
However, Sir Christopher Ingold and Edward D. Hughes, who studied the kinetics of various nucleophilic substitution reactions, noticed that a tertiary alkyl halide does undergo a nucleophilic substitution reaction in the presence of a weak nucleophile. While studying the substitution...

SN1 Reaction: Mechanism

S_N1 Reaction: Mechanism

Kinetic studies of ionization of a tertiary halide in a protic solvent suggest that only the substrate participates in the rate-determining step (slow step). The nucleophile is involved only after the slowest step. The SN1 reaction takes place in a multiple-step mechanism.
Firstly, the haloalkane ionizes to generate a carbocation intermediate and a halide ion. This heterolytic cleavage is highly endothermic with large activation energy. The ionization of the substrate, facilitated by a...

Acidity of 1-Alkynes

Acidity of 1-Alkynes

The acidic strength of hydrocarbons follows the order: Alkynes > Alkenes > Alkanes. The strength of an acid is commonly expressed in units of pKa — the lower the pKa, the stronger the acid. Among the hydrocarbons, terminal alkynes have lower pKa values and are, therefore, more acidic. For example, the pKa values for ethane, ethene, and acetylene are 51, 44, and 25, respectively, as shown here.

Functional Groups

Functional Groups

Functional groups are a group of atoms with characteristic properties, which when linked to the carbon skeleton of a molecule, alter the properties of that molecule. For example, the presence of certain functional groups on a molecule will make them hydrophilic, whereas others will make them hydrophobic. These functional groups are an indispensable part of organic chemistry and important components of biological molecules, such as carbohydrates, proteins, lipids, and nucleic acids. Each...

También podría leer

Artículos Relacionados

Artículos vinculados a este trabajo por autores compartidos, revista y gráfico de citas.

Ordenar por

Same author

Guiding AlphaFold to predict how Munc13-1 opens Syntaxin-1.

FEBS open bio·2026

Same author

The local detergent model of SNARE-mediated membrane fusion.

Journal of cell science·2026

Same author

Evaluation of synaptotagmin-1 action models by all-atom molecular dynamics simulations.

FEBS open bio·2025

Same author

A lever hypothesis for Synaptotagmin-1 action in neurotransmitter release.

Proceedings of the National Academy of Sciences of the United States of America·2025

Same author

Neurotransmitter release is triggered by a calcium-induced rearrangement in the Synaptotagmin-1/SNARE complex primary interface.

Proceedings of the National Academy of Sciences of the United States of America·2024

Same author

A lever hypothesis for Synaptotagmin-1 action in neurotransmitter release.

bioRxiv : the preprint server for biology·2024

Search research articles

Video Experimental Relacionado

Updated: Jan 23, 2026

Measurement of Chladni Mode Shapes with an Optical Lever Method

Measurement of Chladni Mode Shapes with an Optical Lever Method

Published on: June 5, 2020

El modelo de palanca de la función de la sinaptotagmina-1

Josep Rizo^1,2,3, Yun-Zu Pan^1,2,3, Cyrus T Rastegar^1,2,3

¹Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.

Journal of cell science

|January 22, 2026

Resumen

La unión del calcio a la sinaptotagmina-1 (una proteína crucial para la liberación de neurotransmisores) provoca la reorientación de su dominio C2B, actuando como una palanca para desencadenar la fusión rápida de membranas mediante la manipulación del complejo SNARE.

Palabras clave:

Complexina Fusión de membranas Liberación de neurotransmisores SNAREs Sinaptotagmina

Más Videos Relacionados

Modeling Myotonic Dystrophy 1 in C2C12 Myoblast Cells

Modeling Myotonic Dystrophy 1 in C2C12 Myoblast Cells

Published on: July 29, 2016

Myocardial Infarction and Functional Outcome Assessment in Pigs

Myocardial Infarction and Functional Outcome Assessment in Pigs

Published on: April 25, 2014

Videos de Experimentos Relacionados

Last Updated: Jan 23, 2026

Measurement of Chladni Mode Shapes with an Optical Lever Method

Measurement of Chladni Mode Shapes with an Optical Lever Method

Published on: June 5, 2020

Modeling Myotonic Dystrophy 1 in C2C12 Myoblast Cells

Modeling Myotonic Dystrophy 1 in C2C12 Myoblast Cells

Published on: July 29, 2016

Myocardial Infarction and Functional Outcome Assessment in Pigs

Myocardial Infarction and Functional Outcome Assessment in Pigs

Published on: April 25, 2014

Área de la Ciencia:

Neurociencia Molecular
Biología Celular
Biofísica

Sus antecedentes:

La liberación de neurotransmisores depende de la unión de Ca2+ a la sinaptotagmina-1 y a las SNAREs.
El papel de la sinaptotagmina-1 en la fusión de membranas es debatido debido a la orientación del dominio C2.
Los bucles de unión a Ca2+ del dominio C2B de la sinaptotagmina-1 apuntan lejos del sitio de fusión cuando se unen a las SNAREs.

Objetivo del estudio:

Resolver la paradoja de la orientación del dominio C2B de la sinaptotagmina-1 durante la liberación de neurotransmisores.
Proponer un modelo que explique cómo la sinaptotagmina-1 facilita la fusión de membranas mediada por SNARE.

Principales métodos:

Simulaciones de dinámica molecular para evaluar el impacto de la proximidad del dominio C2 a los sitios de fusión.
Técnicas espectroscópicas (RPE, RMN, fluorescencia) para estudiar la reorientación del dominio C2B tras la unión de Ca2+.
Estudios electrofisiológicos para determinar la importancia funcional de la reorientación del dominio C2B.

Principales resultados:

La unión de Ca2+ induce la reorientación del dominio C2B de la sinaptotagmina-1.
El dominio C2B puede disociarse parcialmente del complejo SNARE anclado a la membrana.
Esta reorientación es crucial para la liberación eficiente de neurotransmisores.

Conclusiones:

La sinaptotagmina-1 actúa como una palanca, con la reorientación del dominio C2B inducida por Ca2+ que facilita los cambios conformacionales de SNARE.
Esta acción remota de palanca desencadena la fusión rápida de membranas, explicando la paradoja de la orientación del dominio C2B.
El modelo propuesto integra datos estructurales y funcionales para dilucidar el mecanismo de liberación rápida de neurotransmisores.