From Constructs to Crystals &#8211; Towards Structure Determination of &#946;-barrel Outer Membrane Proteins

Nicholas Noinaj; Stephen Mayclin; Ann M. Stanley; Christine C. Jao; Susan K. Buchanan

doi:10.3791/53245

Da costrutti a cristalli - Verso Struttura Determinazione della β-canna esterna proteine di mem...

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From Constructs to Crystals – Towards Structure Determination of β-barrel Outer Membrane Proteins

Da costrutti a cristalli - Verso Struttura Determinazione della β-canna esterna proteine di membrana

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09:55 min

July 4, 2016

DOI: 10.3791/53245-v

Nicholas Noinaj¹, Stephen Mayclin², Ann M. Stanley^2,3, Christine C. Jao^2,3, Susan K. Buchanan²

¹Department of Biological Sciences, Markey Center for Structural Biology,Purdue University, ²National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK),National Institutes of Health, ³National Institute of General Medical Sciences (NIGMS),National Institutes of Health

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Overview

This article presents protocols for the production of β-barrel outer membrane proteins (OMPs) in sufficient quantities for structural studies. The method aims to facilitate the crystallization and diffraction of these proteins, which are essential for understanding membrane protein folding and transport.

Key Study Components

Area of Science

Structural Biology
Biochemistry
Membrane Proteins

Background

β-barrel OMPs are crucial for various functions in Gram-negative bacteria, mitochondria, and chloroplasts.
Understanding their structure can provide insights into membrane protein dynamics.
Crystallization of these proteins has been a significant bottleneck in structural studies.
Detergent choice for purification and crystallization is often challenging for researchers.

Purpose of Study

To develop a robust method for producing milligram quantities of β-barrel OMPs.
To enable structural determination through X-ray crystallography or NMR spectroscopy.
To address challenges faced by researchers new to this field.

Methods Used

Construction of a T7 expression vector containing the codon optimized target OMP gene.
In vivo expression of the OMP to facilitate membrane integration.
Use of specific detergents for purification and crystallization.
Demonstration of the procedure by experienced researchers in the lab.

Main Results

The method successfully yields β-barrel OMPs suitable for crystallization.
It provides a reliable approach for studying membrane protein insertion.
Researchers can replicate the method with guidance from the protocol.
Demonstrations by experienced personnel enhance understanding of the process.

Conclusions

This method represents a significant advancement in the study of β-barrel OMPs.
It opens new avenues for structural biology research.
Future studies can leverage this technique to explore membrane protein functions.

Frequently Asked Questions

What are β-barrel outer membrane proteins?

β-barrel OMPs are proteins that form channels in the outer membranes of certain cells, playing key roles in transport and communication.

Why is crystallization of OMPs important?

Crystallization allows for detailed structural analysis, which is essential for understanding their function and mechanism.

What challenges do researchers face with OMPs?

Choosing the right detergents for purification and crystallization can be difficult, especially for those new to the field.

Who demonstrated the procedure in this study?

Jeremy Guerin and colleagues from Susan Buchanan's laboratory demonstrated the procedure.

What is the main goal of the method presented?

The main goal is to produce sufficient quantities of β-barrel OMPs for structural determination using X-ray crystallography or NMR spectroscopy.

How can this method benefit future research?

By providing a reliable protocol, it can help researchers explore the structure and function of membrane proteins more effectively.

β' le proteine della membrana esterna (OMP) svolgono molte funzioni all'interno delle membrane esterne di batteri Gram-negativi, mitocondri e cloroplasti. Qui, speriamo di alleviare un noto collo di bottiglia negli studi strutturali presentando protocolli per la produzione di OMP a β cilindri in quantità sufficienti per la determinazione della struttura mediante cristallografia a raggi X o spettroscopia NMR.

L'obiettivo generale di questo metodo è quello di ottenere quantità di milligrammi di proteine beta-barrel della membrana esterna che cristallizzano e si deframmentano. Questo metodo può aiutare a rispondere a domande chiave nel campo del ripiegamento e del trasporto delle proteine di membrana, come ad esempio il modo in cui le proteine beta-barrel vengono inserite nelle membrane cellulari. Il vantaggio principale di questa tecnica è che è robusta per le proteine beta-barrel.

In generale, le persone che non conoscono questo metodo avranno difficoltà, perché la scelta dei detergenti per la purificazione, la cristallizzazione e la defrazione è impegnativa. Jeremy Guerin, un postdoc del laboratorio di Susan Buchanan, dimostrerà la procedura, oltre a me e ai colleghi del laboratorio. Iniziare questa procedura con la costruzione di un vettore di espressione T7 contenente la proteina bersaglio della membrana esterna ottimizzata per il codone, o gene OMP, per l'espressione in vivo alla membrana come descritto nel protocollo di testo.

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