Sodium Laurate, a Novel Protease- and Mass Spectrometry-Compatible Detergent for Mass Spectrometry-Based Membrane Proteomics

Yong Lin,Quanze He,Yi Liu,Songping Liang,Xianchun Wang,Zhonghua Liu,Jianglin Li,Linju Huo,Michael Massiah

doi:10.1371/journal.pone.0059779

Yong Lin, Quanze He + Show 7 more

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https://doi.org/10.1371/journal.pone.0059779

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Journal: PloS one	Publication Date: Mar 28, 2013
Citations: 45	License type: CC BY 4.0

Affiliation: Hunan Agricultural University, Hunan Normal University

Abstract

The hydrophobic nature of most membrane proteins severely complicates their extraction, proteolysis and identification. Although detergents can be used to enhance the solubility of the membrane proteins, it is often difficult for a detergent not only to have a strong ability to extract membrane proteins, but also to be compatible with the subsequent proteolysis and mass spectrometric analysis. In this study, we made evaluation on a novel application of sodium laurate (SL) to the shotgun analysis of membrane proteomes. SL was found not only to lyse the membranes and solubilize membrane proteins as efficiently as SDS, but also to be well compatible with trypsin and chymotrypsin. Furthermore, SL could be efficiently removed by phase transfer method from samples after acidification, thus ensuring not to interfere with the subsequent CapLC-MS/MS analysis of the proteolytic peptides of proteins. When SL was applied to assist the digestion and identification of a standard protein mixture containing bacteriorhodoposin and the proteins in rat liver plasma membrane-enriched fractions, it was found that, compared with other two representative enzyme- and MS-compatible detergents RapiGest SF (RGS) and sodium deoxycholate (SDC), SL exhibited obvious superiority in the identification of membrane proteins particularly those with high hydrophobicity and/or multiple transmembrane domains.

Highlights

Membranes are critical components of cellular structure and play important roles in partitioning of organelles, providing defense against foreign molecules and external conditions that may damage or destroy the cell and so on [1]
The results showed that, compared with RapiGest SF (RGS) and sodium deoxycholate (SDC), two commonly used enzyme- and mass spectrometry (MS)-compatible detergents in membrane proteomics, sodium laurate (SL) was more effective for the extraction and identification of membrane proteins those with strong hydrophobicity and/or multiple transmembrane domains, demonstrating that SL has high potential for the analysis of membrane proteomes
Structure Analysis of Detergents In membrane proteomic studies, the extraction and solubilization of membrane proteins is a critical step, which heavily affects the analytical results of such kind of proteins

Summary

Introduction

Membranes are critical components of cellular structure and play important roles in partitioning of organelles, providing defense against foreign molecules and external conditions that may damage or destroy the cell and so on [1]. The functions of membranes are essentially carried out by membrane proteins. Plasma membrane (PM) proteins are of particular importance because they play important biological and pharmacological roles in regulating the exchange of material and energy between cells and their environments [2,3,4]. Despite the biological importance of membrane proteins especially PM proteins, their analyses have lagged behind that of soluble proteins and still present a great challenge mainly because of their highly hydrophobic nature and low abundance [1,5,6]. How to prepare membrane protein samples for mass spectrometric analysis is a subject worthy of investigation [1,6,7]

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