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  1. Article ; Online: Effects of Amino Acid Additives on Protein Stability during Electrothermal Supercharging in ESI-MS.

    Javanshad, Roshan / Panth, Rajendra / Venter, Andre R

    Journal of the American Society for Mass Spectrometry

    2023  Volume 35, Issue 1, Page(s) 151–157

    Abstract: The surprising formation of highly charged protein ions from aqueous ammonium bicarbonate solution is a fascinating phenomenon referred to as electrothermal supercharging (ETS). Although the precise mechanism involved is not clearly understood, previous ... ...

    Abstract The surprising formation of highly charged protein ions from aqueous ammonium bicarbonate solution is a fascinating phenomenon referred to as electrothermal supercharging (ETS). Although the precise mechanism involved is not clearly understood, previous studies predominantly suggest that ETS is due to native protein destabilization in the presence of bicarbonate anion inside the electrospray ionization droplets under high temperatures and spray voltages. To evaluate existing hypotheses surrounding the underlying mechanism of ETS, the effects of several additives on protein charging under ETS conditions were investigated. The changes in the protein charge state distributions were compared by measuring the ratios between the intensities of
    MeSH term(s) Amino Acids ; Spectrometry, Mass, Electrospray Ionization ; Proteins/chemistry ; Protein Stability ; Proline ; Imidazoles
    Chemical Substances ammonium bicarbonate (45JP4345C9) ; Amino Acids ; Proteins ; Proline (9DLQ4CIU6V) ; Imidazoles
    Language English
    Publishing date 2023-12-11
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1073671-2
    ISSN 1879-1123 ; 1044-0305
    ISSN (online) 1879-1123
    ISSN 1044-0305
    DOI 10.1021/jasms.3c00377
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Effects of amino acid additives on protein solubility - insights from desorption and direct electrospray ionization mass spectrometry.

    Javanshad, Roshan / Venter, Andre R

    The Analyst

    2021  Volume 146, Issue 21, Page(s) 6592–6604

    Abstract: Naturally occurring amino acids have been broadly used as additives to improve protein solubility and inhibit aggregation. In this study, improvements in protein signal intensity obtained with the addition of L-serine, and structural analogs, to the ... ...

    Abstract Naturally occurring amino acids have been broadly used as additives to improve protein solubility and inhibit aggregation. In this study, improvements in protein signal intensity obtained with the addition of L-serine, and structural analogs, to the desorption electrospray ionization mass spectrometry (DESI-MS) spray solvent were measured. The results were interpreted at the hand of proposed mechanisms of solution additive effects on protein solubility and dissolution. DESI-MS allows for these processes to be studied efficiently using dilute concentrations of additives and small amounts of proteins, advantages that represent real benefits compared to classical methods of studying protein stability and aggregation. We show that serine significantly increases the protein signal in DESI-MS when native proteins are undergoing unfolding during the dissolution process with an acidic solvent system (
    MeSH term(s) Amino Acids ; Proteins ; Solubility ; Solvents ; Spectrometry, Mass, Electrospray Ionization
    Chemical Substances Amino Acids ; Proteins ; Solvents
    Language English
    Publishing date 2021-10-25
    Publishing country England
    Document type Journal Article
    ZDB-ID 210747-8
    ISSN 1364-5528 ; 0003-2654
    ISSN (online) 1364-5528
    ISSN 0003-2654
    DOI 10.1039/d1an01392k
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Analysis of histidine-tagged recombinant proteins from nickel and copper coated surfaces by direct electrospray ionization and desorption electrospray ionization mass spectrometry.

    Javanshad, Roshan / Taylor, Christopher James / Delavari, Niusha / Barkman, Todd J / Stull, Frederick / Venter, Andre R

    Rapid communications in mass spectrometry : RCM

    2023  Volume 37 Suppl 1, Page(s) e9516

    Abstract: Rationale: Purification of recombinant proteins is a necessary step for functional or structural studies and other applications. Immobilized metal affinity chromatography is a common recombinant protein purification method. Mass spectrometry (MS) allows ...

    Abstract Rationale: Purification of recombinant proteins is a necessary step for functional or structural studies and other applications. Immobilized metal affinity chromatography is a common recombinant protein purification method. Mass spectrometry (MS) allows for confirmation of identity of expressed proteins and unambiguous detection of enzymatic substrates and reaction products. We demonstrate the detection of enzymes purified on immobilized metal affinity surfaces by direct or ambient ionization MS, and follow their enzymatic reactions by direct electrospray ionization (ESI) or desorption electrospray ionization (DESI).
    Methods: A protein standard, His-Ubq, and two recombinant proteins, His-SHAN and His-CS, expressed in Escherichia coli were immobilized on two immobilized metal affinity systems, Cu-nitriloacetic acid (Cu-NTA) and Ni-NTA. The proteins were purified on surface, and released in the ESI spray solvent for direct infusion, when using the 96-well plate form factor, or analyzed directly from immobilized metal affinity-coated microscope slides by DESI-MS. Enzyme activity was followed by incubating the substrates in wells or by depositing substrate on immobilized protein on coated slides for analysis.
    Results: Small proteins (His-Ubq) and medium proteins (His-SAHN) could readily be detected from 96-well plates by direct infusion ESI, or from microscope slides by DESI-MS after purification on surface from clarified E. coli cell lysate. Protein oxidation was observed for immobilized proteins on both Cu-NTA and Ni-NTA; however, this did not hamper the enzymatic reactions of these proteins. Both the nucleosidase reaction products for His-SAHN and the methylation product of His-CS (theobromine to caffeine) were detected.
    Conclusions: The immobilization, purification, release and detection of His-tagged recombinant proteins using immobilized metal affinity surfaces for direct infusion ESI-MS or ambient DESI-MS analyses were successfully demonstrated. Recombinant proteins were purified to allow identification directly out of clarified cell lysate. Biological activities of the recombinant proteins were preserved allowing the investigation of enzymatic activity via MS.
    MeSH term(s) Spectrometry, Mass, Electrospray Ionization/methods ; Copper ; Nickel ; Histidine/chemistry ; Escherichia coli/genetics ; Indicators and Reagents ; Recombinant Proteins/genetics
    Chemical Substances cupric nitrilotriacetate (D034E84B7S) ; Copper (789U1901C5) ; Nickel (7OV03QG267) ; Histidine (4QD397987E) ; Indicators and Reagents ; Recombinant Proteins
    Language English
    Publishing date 2023-04-24
    Publishing country England
    Document type Journal Article
    ZDB-ID 58731-x
    ISSN 1097-0231 ; 0951-4198
    ISSN (online) 1097-0231
    ISSN 0951-4198
    DOI 10.1002/rcm.9516
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    Zs.A 3461: Show issues Location:
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  4. Article ; Online: Addition of Serine Enhances Protein Analysis by DESI-MS.

    Javanshad, Roshan / Honarvar, Elahe / Venter, Andre R

    Journal of the American Society for Mass Spectrometry

    2019  Volume 30, Issue 4, Page(s) 694–703

    Abstract: Previous studies have suggested that the loss in sensitivity of DESI-MS for large molecules such as proteins is due to the poor dissolution during the short time scale of desorption and ionization. An investigation into the effect of serine as a solvent ... ...

    Abstract Previous studies have suggested that the loss in sensitivity of DESI-MS for large molecules such as proteins is due to the poor dissolution during the short time scale of desorption and ionization. An investigation into the effect of serine as a solvent additive leads to the interesting observation that there is a concentration-dependent improvement in protein signal intensity when micromolar to low millimolar concentrations of serine is combined with a suitable co-additive in DESI spray. This effect, however, was not observed during similar ESI-MS experiments, where the same solvents and proteins were sprayed directly into the MS inlet. This suggests that the mechanism of signal improvement in DESI is associated with the desorption step of proteins, possibly by facilitating dissolution or improving solubility of proteins on the surface in the solvent micro-layer formed during DESI. Other than poor dissolution, cation adduction such as by sodium ions is also a major contributing factor to the mass-dependent loss in sensitivity in both ESI and DESI, leading to an increase in limits of detection for larger proteins. The adduction becomes a more pressing issue in native-state studies of proteins, as lower charge states are more susceptible to adduction. Previous studies have shown that addition of amino acids to the working spray solution during ESI-MS reduces sodium adduction and can help in stabilization of native-state proteins. Similar to the observed reduction in sodium adducts during native-state ESI-MS, when serine is added to the desorbing spray in DESI-MS, the removal of up to 10 mM NaCl is shown. A selection of proteins with high and low pI and molecular weights was analyzed to investigate the effects of serine on signal intensity by improvements in protein solubility and adduct removal. Graphical Abstract.
    MeSH term(s) Animals ; Cations/chemistry ; Cattle ; Cytochromes c/analysis ; Horses ; Protein Stability ; Proteins/analysis ; Serine/chemistry ; Sodium/chemistry ; Sodium Chloride/chemistry ; Solubility ; Solvents/chemistry ; Spectrometry, Mass, Electrospray Ionization/methods
    Chemical Substances Cations ; Proteins ; Solvents ; Sodium Chloride (451W47IQ8X) ; Serine (452VLY9402) ; Cytochromes c (9007-43-6) ; Sodium (9NEZ333N27)
    Language English
    Publishing date 2019-02-15
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1073671-2
    ISSN 1879-1123 ; 1044-0305
    ISSN (online) 1879-1123
    ISSN 1044-0305
    DOI 10.1007/s13361-018-02129-8
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Endogenous Protein-Protein Interaction Network of the NPC Cholesterol Transporter 1 in the Cerebral Cortex.

    Javanshad, Roshan / Nguyen, Thu T A / Azaria, Ruth D / Li, Wenping / Edmison, Daisy / Gong, Liang-Wei / Gowrishankar, Swetha / Lieberman, Andrew P / Schultz, Mark L / Cologna, Stephanie M

    Journal of proteome research

    2024  

    Abstract: NPC intracellular cholesterol transporter 1 (NPC1) is a multipass, transmembrane glycoprotein mostly recognized for its key role in facilitating cholesterol efflux. Mutations in ... ...

    Abstract NPC intracellular cholesterol transporter 1 (NPC1) is a multipass, transmembrane glycoprotein mostly recognized for its key role in facilitating cholesterol efflux. Mutations in the
    Language English
    Publishing date 2024-04-30
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2078618-9
    ISSN 1535-3907 ; 1535-3893
    ISSN (online) 1535-3907
    ISSN 1535-3893
    DOI 10.1021/acs.jproteome.3c00788
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  6. Article ; Online: The Addition of Polar Organic Solvent Vapors During the Analysis of Proteins by DESI-MS.

    Javanshad, Roshan / Maser, Tara L / Honarvar, Elahe / Venter, Andre R

    Journal of the American Society for Mass Spectrometry

    2019  Volume 30, Issue 12, Page(s) 2571–2575

    Abstract: Exposure of electrospray droplets to organic vapors was shown to dramatically reduce alkali-metal adduction on protein ions and shift protein charge states. Since DESI-MS is affected by similar adduct species as ESI-MS and shares similar ionization ... ...

    Abstract Exposure of electrospray droplets to organic vapors was shown to dramatically reduce alkali-metal adduction on protein ions and shift protein charge states. Since DESI-MS is affected by similar adduct species as ESI-MS and shares similar ionization mechanisms, polar organic vapor additives should likewise also improve the DESI-MS analysis of proteins. Here the DESI spray was exposed to a variety of polar organic vapor additives. Head space vapors of polar organic solvents were entrained in nitrogen gas and delivered to the atmosphere inside a semi-enclosed plastic enclosure surrounding the spray plume. The vapors of acetone, acetonitrile, ethyl acetate, methanol, and water were investigated. Vapor dependent effects were observed with respect to changes in protein charge state distributions and signal intensities. With ethyl acetate vapor addition, the signal intensities of all proteins investigated were significantly increased, including proteins larger than 25 kDa such as carbonic anhydrase II and bovine serum albumin.
    MeSH term(s) Acetates/chemistry ; Acetone/chemistry ; Acetonitriles/chemistry ; Animals ; Carbonic Anhydrase II/analysis ; Cattle ; Cytochromes c/analysis ; Equipment Design ; Horses ; Methanol/chemistry ; Proteins/analysis ; Serum Albumin, Bovine/analysis ; Solvents/chemistry ; Spectrometry, Mass, Electrospray Ionization/instrumentation ; Spectrometry, Mass, Electrospray Ionization/methods ; Volatilization ; Water/chemistry
    Chemical Substances Acetates ; Acetonitriles ; Proteins ; Solvents ; Water (059QF0KO0R) ; Acetone (1364PS73AF) ; Serum Albumin, Bovine (27432CM55Q) ; ethyl acetate (76845O8NMZ) ; Cytochromes c (9007-43-6) ; Carbonic Anhydrase II (EC 4.2.1.-) ; Methanol (Y4S76JWI15) ; acetonitrile (Z072SB282N)
    Language English
    Publishing date 2019-11-22
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1073671-2
    ISSN 1879-1123 ; 1044-0305
    ISSN (online) 1879-1123
    ISSN 1044-0305
    DOI 10.1007/s13361-019-02345-w
    Database MEDical Literature Analysis and Retrieval System OnLINE

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