Nanoliter Chemistry Combined with Mass Spectrometry for Peptide Mapping of Proteins from Single Mammalian Cell Lysates

1998 ◽  
Vol 70 (24) ◽  
pp. 5344-5347 ◽  
Author(s):  
Randy M. Whittal ◽  
Bernd O. Keller ◽  
Liang Li
1996 ◽  
Vol 118 (46) ◽  
pp. 11662-11663 ◽  
Author(s):  
Liang Li ◽  
Rafael E. Golding ◽  
Randy M. Whittal

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.


Amino Acids ◽  
2021 ◽  
Author(s):  
Magdalena Widgren Sandberg ◽  
Jakob Bunkenborg ◽  
Stine Thyssen ◽  
Martin Villadsen ◽  
Thomas Kofoed

AbstractGranulocyte-macrophage colony-stimulating factor (GM-CSF) is a cytokine and a white blood cell growth factor that has found usage as a therapeutic protein. During analysis of different fermentation batches of GM-CSF recombinantly expressed in E. coli, a covalent modification was identified on the protein by intact mass spectrometry. The modification gave a mass shift of + 70 Da and peptide mapping analysis demonstrated that it located to the protein N-terminus and lysine side chains. The chemical composition of C4H6O was found to be the best candidate by peptide fragmentation using tandem mass spectrometry. The modification likely contains a carbonyl group, since the mass of the modification increased by 2 Da by reduction with borane pyridine complex and it reacted with 2,4-dinitrophenylhydrazine. On the basis of chemical and tandem mass spectrometry fragmentation behavior, the modification could be attributed to crotonaldehyde, a reactive compound formed during lipid peroxidation. A low recorded oxygen pressure in the reactor during protein expression could be linked to the formation of this compound. This study shows the importance of maintaining full control over all reaction parameters during recombinant protein production.


2020 ◽  
Vol 20 ◽  
Author(s):  
Bryan Fonslow ◽  
Gabor Jarvas ◽  
Marton Szigeti ◽  
Andras Guttman

Aims: Demonstrating the capabilities of our new capillary electrophoresis – mass spectrometry method, which facilitates highly accurate relative quantitation of modification site occupancy of antibody-ligand (e.g., antibody-drug) conjugates. Background: Antibody-drug conjugates play important roles in medical discovery for imaging and therapeutic intervention. The localization and stoichiometry of the conjugation can affect the orientation, selectivity, specificity, and strength of molecular interactions, influencing biochemical function. Objective: To demonstrate the option to analyze the localization and stoichiometry of antibody-ligand conjugates by using essentially the same method at all levels including ligand infusion, peptide mapping, as well as reduced and intact protein analysis. Materials and Methods: Capillary electrophoresis coupled to electrospray ionization mass spectrometry was used to analyze the antibodyligand conjugates. Results: We identified three prevalent ligand conjugation sites with estimated stoichiometries of 73, 14, and 6% and an average ligand-antibody ratio of 1.37, illustrating the capabilities of CE-ESI-MS for rapid and efficient characterization of antibody-drug conjugates. Conclusion: The developed multilevel analytical method offers a comprehensive way to determine the localization and stoichiometry of antibody-drug conjugates for molecular medicinal applications. In addition, a significant advantage of the reported approach is that small, hydrophilic, unmodified peptides well separated from the neutrals, which is not common with other liquid phase separation methods such as LC.


Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Dongdong Zhang ◽  
Abhinav Srinath ◽  
Andrew J Kinloch ◽  
Robert Shenkar ◽  
Le Shen ◽  
...  

Introduction: Previous studies have reported robust inflammatory cell infiltration, selective synthesis of IgG, B-cell clonal expansion, and deposition of immune complexes and complement within Cerebral Cavernous Malformation (CCM) lesions. Furthermore,B-cell depletion has been shown to reduce the maturation of CCM in murine models. We hypothesize that specific autoantigen(s) within the lesional milieu trigger the pathogenetic immune responses in CCMs. This study aims to identify those putative autoantigen(s) using recombinant antibodies (rAbs) derived from plasma cells found in surgical human CCM lesions. Methods: CD138 + plasma cells were laser captured from fresh frozen surgically resected human CCM lesions. Clonally expanded immunoglobulin heavy- and light-chain variable region pairs were cloned into IgG expression vectors and expressed as monoclonal antibodies. Purified rAbs were assayed by immunofluorescence with CCM lesion tissue and normal brain tissue sections. rAbs assayed by immunocytochemistry with human primary cell line were used to further define the staining pattern. The cell lysates were immunoprecipitated with rAb, after protein purification by SDS-PAGE, and analyzed by Mass spectrometry. Results: In normal brain tissue, rAbs stained endothelial cells with limited staining of glial cells. In CCM lesional tissue, rAbs stained endothelial cells, glial cells as well as structures in the acellular matrix adjacent to caverns. In cultured Human Brain Microvascular Endothelial Cells (HBMECs) and Human Astrocytes (HAs), rAbs co-localized with cytoplasmic components. After HBMEC and HA cell lysates were immunoprecipitated with rAb, a Coomassie Stain detected bands of approximately 50 kDa. Conclusions: Our results suggest that autoantigen(s) in human CCM lesions are cytoplasmic components present in lesional tissue as well as in normal brain tissue. Molecular level identification of the triggering antigen is still ongoing by mass spectrometry. Identification of the autoantigen(s) in the lesional milieu might explain the propensity of lesion development from leaky endothelium in the neuroglial parenchyma. Characterization of the autoantigen triggers will open new venues for therapy or vaccine in this disease.


2021 ◽  
Author(s):  
Yongzheng Cong ◽  
Khatereh Motamedchaboki ◽  
Santosh A. Misal ◽  
Yiran Liang ◽  
Amanda J. Guise ◽  
...  

The combination of nanodroplet sample preparation, ultra-low-flow nanoLC, high-field asymmetric ion mobility spectrometry (FAIMS) and latest-generation mass spectrometry instrumentation provides dramatically improved single-cell proteome profiling.


2006 ◽  
Vol 6 ◽  
pp. 589-614 ◽  
Author(s):  
Yan Lu ◽  
Song Hong ◽  
Katherine Gotlinger ◽  
Charles Serhan

Lipid mediator informatics is an emerging area denoted to the identification of bioactive lipid mediators (LMs) and their biosynthetic profiles and pathways. LM informatics and proteomics applied to inflammation, systems tissues research provides a powerful means of uncovering key biomarkers for novel processes in health and disease. By incorporating them with system biology analysis, we review here our initial steps toward elucidating relationships among a range of bimolecular classes and provide an appreciation of their roles and activities in the pathophysiology of disease. LM informatics employing liquid chromatography-ultraviolet-tandem mass spectrometry (LC-UV-MS/MS), gas chromatography-mass spectrometry (GC-MS), computer-based automated systems equipped with databases and novel searching algorithms, and enzyme-linked immunosorbent assay (ELISA) to evaluate and profile temporal and spatial production of mediators combined with proteomics at defined points during experimental inflammation and its resolution enable us to identify novel mediators in resolution. The automated system including databases and searching algorithms is crucial for prompt and accurate analysis of these lipid mediators biosynthesized from precursor polyunsaturated fatty acids such as eicosanoids, resolvins, and neuroprotectins, which play key roles in human physiology and many prevalent diseases, especially those related to inflammation. This review presents detailed protocols used in our lab for LM informatics and proteomics using LC-UV-MS/MS, GC-MS, ELISA, novel databases and searching algorithms, and 2-dimensional gel electrophoresis and LC-nanospray-MS/MS peptide mapping.


Separations ◽  
2020 ◽  
Vol 7 (2) ◽  
pp. 25 ◽  
Author(s):  
Eduardo Sommella ◽  
Emanuela Salviati ◽  
Simona Musella ◽  
Veronica Di Sarno ◽  
Francesco Gasparrini ◽  
...  

In this work, two online comprehensive two-dimensional liquid chromatography platforms, namely Hydrophilic interaction liquid chromatography × Reversed phase (HILIC × RP) and Reversed phase × Reversed Phase (RP × RP) coupled to mass spectrometry, were compared for the analysis of complex peptide samples. In the first dimension, a HILIC Amide and C18 Bioshell peptide (150 × 2.1 mm, 1.7 and 2.0 μm) columns were selected, while, in the second dimension, a short C18 (50 × 3.0 mm, 2.7 μm) Bioshell peptide column was used. Two C18 trapping columns (10 × 3.0 mm, 1.9 μm), characterized by high retention and surface area, were employed as modulation interface in both HILIC × RP and RP × RP methods. The LC × LC platforms were coupled to UV and tandem mass spectrometry detection and tested for the separation and identification of two gastro-intestinal digests of commercial microalgae formulations (Spirulina Platensis and Klamath). Their performances were evaluated in terms of peak capacity, maximum number and properties of identified phycocyanin peptides. Our results showed that the HILIC × RP approach provided the highest peak capacity values (nc HILIC × RP: 932 vs. nc RP × RP: 701) with an analysis time of 60 min, while the RP × RP approach was able to identify a slight higher number of phycocyanin derived peptides (HILIC × RP: 88 vs. RP × RP: 103). These results point out the flexibility and potential of HILIC × RP and RP × RP based on trapping modulation for peptide mapping approaches.


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