PEPPI-MS: Strategies to Enhance the Extraction of Electrophoretically Separated Proteins from Polyacrylamide Gels and Their Application to Top-Down/native Mass Spectrometry

Author(s):  
Ayako Takemori ◽  
Lissa C Anderson ◽  
Victoria M. Harman ◽  
Philip Brownridge ◽  
David Butcher ◽  
...  

Polyacrylamide gel electrophoresis (PAGE) is a powerful technique for separating proteins from complex biological samples. However, the difficulty in recovering proteins with high yields from polyacrylamide matrices often precludes further analyses of intact proteins. Here, we propose a novel experimental workflow named Passively Eluting Proteins from Polyacrylamide gels as Intact species for MS (‘PEPPI-MS’), which allows intact mass spectrometry (MS) of PAGE separated proteins. We discovered that staining proteins with certain Coomassie brilliant blue formulations immediately after PAGE improves the efficiency of extraction in a medium with pH 7–11. Post-staining, proteins spanning a broad range of molecular weights were recovered efficiently in a 10-minute procedure. High recovery yields were also obtained from dried and archived gels. This workflow is effective for top-down proteomics analysis of the target molecular region in the gel. An alternative procedure was developed for the extraction of protein complexes exceeding 400 kDa, which were separated using native PAGE, from unstained gels. Non-covalent hemoglobin tetramer, purified from cell lysate with two-dimensional native PAGE and extracted with the mild detergent octyl-β-Dglucopyranoside, was amenable for native MS analysis. We anticipate that the established workflow will facilitate the purification, storage, and transport of proteins destined for detailed characterization by MS.

2019 ◽  
Author(s):  
Ayako Takemori ◽  
Lissa C Anderson ◽  
Victoria M. Harman ◽  
Philip Brownridge ◽  
David Butcher ◽  
...  

Polyacrylamide gel electrophoresis (PAGE) is a powerful technique for separating proteins from complex biological samples. However, the difficulty in recovering proteins with high yields from polyacrylamide matrices often precludes further analyses of intact proteins. Here, we propose a novel experimental workflow named Passively Eluting Proteins from Polyacrylamide gels as Intact species for MS (‘PEPPI-MS’), which allows intact mass spectrometry (MS) of PAGE separated proteins. We discovered that staining proteins with certain Coomassie brilliant blue formulations immediately after PAGE improves the efficiency of extraction in a medium with pH 7–11. Post-staining, proteins spanning a broad range of molecular weights were recovered efficiently in a 10-minute procedure. High recovery yields were also obtained from dried and archived gels. This workflow is effective for top-down proteomics analysis of the target molecular region in the gel. An alternative procedure was developed for the extraction of protein complexes exceeding 400 kDa, which were separated using native PAGE, from unstained gels. Non-covalent hemoglobin tetramer, purified from cell lysate with two-dimensional native PAGE and extracted with the mild detergent octyl-β-Dglucopyranoside, was amenable for native MS analysis. We anticipate that the established workflow will facilitate the purification, storage, and transport of proteins destined for detailed characterization by MS.


2019 ◽  
Vol 437 ◽  
pp. 23-29 ◽  
Author(s):  
Rian L. Griffiths ◽  
Emma K. Sisley ◽  
Andrea F. Lopez-Clavijo ◽  
Anna L. Simmonds ◽  
Iain B. Styles ◽  
...  

2019 ◽  
Author(s):  
Zachary VanAernum ◽  
Florian Busch ◽  
Benjamin J. Jones ◽  
Mengxuan Jia ◽  
Zibo Chen ◽  
...  

It is important to assess the identity and purity of proteins and protein complexes during and after protein purification to ensure that samples are of sufficient quality for further biochemical and structural characterization, as well as for use in consumer products, chemical processes, and therapeutics. Native mass spectrometry (nMS) has become an important tool in protein analysis due to its ability to retain non-covalent interactions during measurements, making it possible to obtain protein structural information with high sensitivity and at high speed. Interferences from the presence of non-volatiles are typically alleviated by offline buffer exchange, which is timeconsuming and difficult to automate. We provide a protocol for rapid online buffer exchange (OBE) nMS to directly screen structural features of pre-purified proteins, protein complexes, or clarified cell lysates. Information obtained by OBE nMS can be used for fast (<5 min) quality control and can further guide protein expression and purification optimization.


2021 ◽  
Vol 51 (1) ◽  
Author(s):  
Arthur Laganowsky ◽  
David E. Clemmer ◽  
David H. Russell

The structures and conformational dynamics of proteins, protein complexes, and their noncovalent interactions with other molecules are controlled specifically by the Gibbs free energy (entropy and enthalpy) of the system. For some organisms, temperature is highly regulated, but the majority of biophysical studies are carried out at room, nonphysiological temperature. In this review, we describe variable-temperature electrospray ionization (vT-ESI) mass spectrometry (MS)-based studies with unparalleled sensitivity, dynamic range, and selectivity for studies of both cold- and heat-induced chemical processes. Such studies provide direct determinations of stabilities, reactivities, and thermodynamic measurements for native and non-native structures of proteins and protein complexes and for protein–ligand interactions. Highlighted in this review are vT-ESI-MS studies that reveal 40 different conformers of chymotrypsin inhibitor 2, a classic two-state (native → unfolded) unfolder, and thermochemistry for a model membrane protein system binding lipid and its regulatory protein. Expected final online publication date for the Annual Review of Biophysics, Volume 51 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.


Planta Medica ◽  
2018 ◽  
Vol 84 (16) ◽  
pp. 1201-1212
Author(s):  
Ahad Khan ◽  
Anne Bresnick ◽  
Sean Cahill ◽  
Mark Girvin ◽  
Steve Almo ◽  
...  

AbstractNative mass spectrometry detection of ligand-protein complexes allowed rapid detection of natural product binders of apo and calcium-bound S100A4 (a member of the metal binding protein S100 family), T cell/transmembrane, immunoglobulin (Ig), and mucin protein 3, and T cell immunoreceptor with Ig and ITIM (immunoreceptor tyrosine-based inhibitory motif) domains precursor protein from extracts and fractions. Based on molecular weight common hits were detected binding to all four proteins. Seven common hits were identified as apigenin 6-C-β-D-glucoside 8-C-α-L-arabinoside, sweroside, 4′,5-dihydroxy-7-methoxyflavanone-6-C-rutinoside, loganin acid, 6-C-glucosylnaringenin, biochanin A 7-O-rutinoside and quercetin 3-O-rutinoside. Mass guided isolation and NMR identification of hits confirmed the mass accuracy of the ligand in the ligand-protein MS complexes. Thus, molecular weight ID from ligand-protein complexes by electrospray ionization Fourier transform mass spectrometry allowed rapid dereplication. Native mass spectrometry using electrospray ionization Fourier transform mass spectrometry is a tool for dereplication and metabolomics analysis.


2018 ◽  
Vol 90 (4) ◽  
pp. 2756-2764 ◽  
Author(s):  
Daniel A. Polasky ◽  
Frederik Lermyte ◽  
Michael Nshanian ◽  
Frank Sobott ◽  
Phillip C. Andrews ◽  
...  

2008 ◽  
Vol 41 (6) ◽  
pp. 1150-1160 ◽  
Author(s):  
Jichun Ma ◽  
Di Xia

Crystallization has long been one of the bottlenecks in obtaining structural information at atomic resolution for membrane proteins. This is largely due to difficulties in obtaining high-quality protein samples. One frequently used indicator of protein quality for successful crystallization is the monodispersity of proteins in solution, which is conventionally obtained by size exclusion chromatography (SEC) or by dynamic light scattering (DLS). Although useful in evaluating the quality of soluble proteins, these methods are not always applicable to membrane proteins either because of the interference from detergent micelles or because of the requirement for large sample quantities. Here, the use of blue native polyacrylamide gel electrophoresis (BN–PAGE) to assess aggregation states of membrane protein samples is reported. A strong correlation is demonstrated between the monodispersity measured by BN–PAGE and the propensity for crystallization of a number of soluble and membrane protein complexes. Moreover, it is shown that there is a direct correspondence between the oligomeric states of proteins as measured by BN–PAGE and those obtained from their crystalline forms. When applied to a membrane protein with unknown structure, BN–PAGE was found to be useful and efficient for selecting well behaved proteins from various constructs and in screening detergents. Comparisons of BN–PAGE with DLS and SEC are provided.


2012 ◽  
Vol 11 (11) ◽  
pp. 1430-1441 ◽  
Author(s):  
Esther van Duijn ◽  
Ioana M. Barbu ◽  
Arjan Barendregt ◽  
Matthijs M. Jore ◽  
Blake Wiedenheft ◽  
...  

The CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR-associated genes) immune system of bacteria and archaea provides acquired resistance against viruses and plasmids, by a strategy analogous to RNA-interference. Key components of the defense system are ribonucleoprotein complexes, the composition of which appears highly variable in different CRISPR/Cas subtypes. Previous studies combined mass spectrometry, electron microscopy, and small angle x-ray scattering to demonstrate that the E. coli Cascade complex (405 kDa) and the P. aeruginosa Csy-complex (350 kDa) are similar in that they share a central spiral-shaped hexameric structure, flanked by associating proteins and one CRISPR RNA. Recently, a cryo-electron microscopy structure of Cascade revealed that the CRISPR RNA molecule resides in a groove of the hexameric backbone. For both complexes we here describe the use of native mass spectrometry in combination with ion mobility mass spectrometry to assign a stable core surrounded by more loosely associated modules. Via computational modeling subcomplex structures were proposed that relate to the experimental IMMS data. Despite the absence of obvious sequence homology between several subunits, detailed analysis of sub-complexes strongly suggests analogy between subunits of the two complexes. Probing the specific association of E. coli Cascade/crRNA to its complementary DNA target reveals a conformational change. All together these findings provide relevant new information about the potential assembly process of the two CRISPR-associated complexes.


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