Submillisecond Conformational Changes in Proteins Resolved by Photothermal Beam Deflection

Walter G. Gonzalez; Jaroslava Miksovska

doi:10.3791/50969

Submillisecond Cambios conformacionales en proteínas resueltas por fototérmica Desviación de haz

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Chemistry

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JoVE Journal Chemistry

Submillisecond Conformational Changes in Proteins Resolved by Photothermal Beam Deflection

Submillisecond Cambios conformacionales en proteínas resueltas por fototérmica Desviación de haz

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10:02 min

February 18, 2014

DOI: 10.3791/50969-v

Walter G. Gonzalez¹, Jaroslava Miksovska¹

¹Department of Chemistry and Biochemistry,Florida International University

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Overview

This study utilizes the photothermal beam deflection technique alongside a caged calcium compound, DM-nitrophen, to investigate the dynamics of structural changes in neuronal calcium sensors. The focus is on the microsecond and millisecond timescales of calcium binding events.

Key Study Components

Area of Science

Neuroscience
Biophysics
Structural Biology

Background

Calcium transducers play a critical role in neuronal signaling.
Understanding conformational changes is essential for elucidating calcium signaling mechanisms.
Photothermal beam deflection offers a novel approach to study these rapid dynamics.
DM-nitrophen is a caged calcium compound that allows for controlled calcium release.

Purpose of Study

To characterize conformational changes associated with ligand binding to calcium transducers.
To measure the dynamics of these changes on a sub-millisecond timescale.
To analyze the reaction volume and enthalpy changes during calcium binding.

Methods Used

Application of photothermal beam deflection technique.
Use of DM-nitrophen for photo release of free calcium.
Measurement of index of reflection changes as a displacement of the probe beam.
Analysis of photothermal beam deflection traces as a function of temperature.

Main Results

Successful measurement of conformational transitions between APO and calcium-bound proteins.
Insights into the mechanism of calcium-induced conformational switches.
Demonstration of simultaneous detection of volume and entropy changes.
Advantages of photothermal beam deflection over traditional methods highlighted.

Conclusions

The study provides a deeper understanding of calcium signaling dynamics.
Photothermal beam deflection is a valuable tool for studying rapid molecular changes.
Future research can build on these findings to explore other calcium-related processes.

Frequently Asked Questions

What is the significance of using DM-nitrophen?

DM-nitrophen allows for controlled release of calcium, enabling precise studies of calcium binding dynamics.

How does photothermal beam deflection work?

It measures changes in the index of reflection caused by conformational changes in proteins when calcium binds.

What are the advantages of this technique?

It allows for simultaneous detection of volume and entropy changes on a sub-millisecond timescale.

What are the implications of this research?

Understanding calcium signaling can lead to insights into various neurological processes and disorders.

Can this method be applied to other proteins?

Yes, the technique can potentially be adapted to study other calcium-binding proteins and their dynamics.

What future research directions does this open?

Future studies could explore different ligands and their effects on calcium transducer dynamics.

Aquí se presenta una aplicación de la técnica de deflexión de haz fototérmica en combinación con un compuesto de calcio enjaulado, DM-nitrofen, para supervisar microsegundos y milisegundos dinámica y de la energética de cambios estructurales asociados con la asociación de calcio a un sensor de calcio neuronal, elemento regulador aguas abajo Antagonista Modulador .

El objetivo general del siguiente experimento es caracterizar los cambios de confirmación asociados con la unión del ligando a los transductores de calcio en una escala de tiempo de menos de un milisegundo. La transición de confirmación entre la proteína APO y la proteína unida al calcio se desencadena por la fotoescisión de un compuesto de calcio enjaulado, calcio DM nitro, que conduce a la fotoliberación de calcio libre. El cambio asociado en el índice de reflexión se mide como un desplazamiento del haz de la sonda utilizando un detector sensible a la posición cuádruple.

A continuación, se miden las trazas de deflexión del haz fototérmico en función de la temperatura tanto para la muestra como para la referencia. El análisis compuesto de las trazas de deflexión del fotohaz proporciona información sobre el mecanismo del interruptor de confirmación inducido por el calcio en términos de cambios en el volumen de reacción y la entalpía. La principal ventaja de la deflexión del haz fototérmico sobre el mástil existente, como el flujo superior, es que esta técnica permite una detección simultánea de cambios de volumen y entropía en una escala de tiempo de menos de un milisegundo.

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