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Lantz C, Lopez J, Goring AK, Zenaidee MA, Biggs K, Whitelegge JP, Ogorzalek Loo RR, Klärner FG, Schrader T, Bitan G, Loo JA. Characterization of Molecular Tweezer Binding on α-Synuclein with Native Top-Down Mass Spectrometry and Ion Mobility-Mass Spectrometry Reveals a Mechanism for Aggregation Inhibition. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:2739-2747. [PMID: 37936057 PMCID: PMC10959575 DOI: 10.1021/jasms.3c00281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2023]
Abstract
Parkinson's disease, a neurodegenerative disease that affects 15 million people worldwide, is characterized by deposition of α-synuclein into Lewy Bodies in brain neurons. Although this disease is prevalent worldwide, a therapy or cure has yet to be found. Several small compounds have been reported to disrupt fibril formation. Among these compounds is a molecular tweezer known as CLR01 that targets lysine and arginine residues. This study aims to characterize how CLR01 interacts with various proteoforms of α-synuclein and how the structure of α-synuclein is subsequently altered. Native mass spectrometry (nMS) measurements of α-synuclein/CLR01 complexes reveal that multiple CLR01 molecules can bind to α-synuclein proteoforms such as α-synuclein phosphorylated at Ser-129 and α-synuclein bound with copper and manganese ions. The binding of one CLR01 molecule shifts the ability for α-synuclein to bind other ligands. Electron capture dissociation (ECD) with Fourier transform-ion cyclotron resonance (FT-ICR) top-down (TD) mass spectrometry of α-synuclein/CLR01 complexes pinpoints the locations of the modifications on each proteoform and reveals that CLR01 binds to the N-terminal region of α-synuclein. CLR01 binding compacts the gas-phase structure of α-synuclein, as shown by ion mobility-mass spectrometry (IM-MS). These data suggest that when multiple CLR01 molecules bind, the N-terminus of α-synuclein shifts toward a more compact state. This compaction suggests a mechanism for CLR01 halting the formation of oligomers and fibrils involved in many neurodegenerative diseases.
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Affiliation(s)
- Carter Lantz
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095 USA
| | - Jaybree Lopez
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095 USA
| | - Andrew K. Goring
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095 USA
| | - Muhammad A. Zenaidee
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095 USA
- Australian Proteome Analysis Facility, Macquarie University, Macquarie Park, NSW, Australia
| | - Karl Biggs
- Department of Neurology and Brain Research Institute, David Geffen School of Medicine at UCLA, University of California-Los Angeles, Los Angeles, CA 90095 USA
| | - Julian P. Whitelegge
- The Pasarow Mass Spectrometry Laboratory, The Jane and Terry Semel Institute for Neuroscience and Human Behavior, David Geffen School of Medicine at UCLA, University of California-Los Angeles, Los Angeles, CA 90095 USA
| | - Rachel R. Ogorzalek Loo
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095 USA
| | | | - Thomas Schrader
- Institute of Chemistry, University of Duisburg-Essen, Essen, Germany
| | - Gal Bitan
- Australian Proteome Analysis Facility, Macquarie University, Macquarie Park, NSW, Australia
- Molecular Biology Institute, University of California-Los Angeles, Los Angeles, CA, 90095 USA
| | - Joseph A. Loo
- Department of Chemistry and Biochemistry, University of California-Los Angeles, Los Angeles, CA 90095 USA
- Molecular Biology Institute, University of California-Los Angeles, Los Angeles, CA, 90095 USA
- Department of Biological Chemistry, David Geffen School of Medicine at UCLA, University of California-Los Angeles, Los Angeles, CA 90095 USA
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2
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de Bruyn E, Dorn AE, Zimmermann O, Rossetti G. SPEADI: Accelerated Analysis of IDP-Ion Interactions from MD-Trajectories. BIOLOGY 2023; 12:biology12040581. [PMID: 37106781 PMCID: PMC10135740 DOI: 10.3390/biology12040581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/04/2023] [Accepted: 04/05/2023] [Indexed: 04/29/2023]
Abstract
The disordered nature of Intrinsically Disordered Proteins (IDPs) makes their structural ensembles particularly susceptible to changes in chemical environmental conditions, often leading to an alteration of their normal functions. A Radial Distribution Function (RDF) is considered a standard method for characterizing the chemical environment surrounding particles during atomistic simulations, commonly averaged over an entire or part of a trajectory. Given their high structural variability, such averaged information might not be reliable for IDPs. We introduce the Time-Resolved Radial Distribution Function (TRRDF), implemented in our open-source Python package SPEADI, which is able to characterize dynamic environments around IDPs. We use SPEADI to characterize the dynamic distribution of ions around the IDPs Alpha-Synuclein (AS) and Humanin (HN) from Molecular Dynamics (MD) simulations, and some of their selected mutants, showing that local ion-residue interactions play an important role in the structures and behaviors of IDPs.
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Affiliation(s)
- Emile de Bruyn
- Jülich Supercomputing Centre, Forschungszentrum Jülich, 52425 Jülich, Germany
- Faculty of Mathematics, Computer Science and Natural Sciences, RWTH Aachen University, 52062 Aachen, Germany
| | - Anton Emil Dorn
- Faculty of Mathematics, Computer Science and Natural Sciences, RWTH Aachen University, 52062 Aachen, Germany
| | - Olav Zimmermann
- Jülich Supercomputing Centre, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Giulia Rossetti
- Jülich Supercomputing Centre, Forschungszentrum Jülich, 52425 Jülich, Germany
- Computational Biomedicine, Institute for Advanced Simulation IAS-5 and Institute of Neuroscience and Medicine INM-9, Forschungszentrum Jülich, 52425 Jülich, Germany
- Department of Neurology, RWTH Aachen University, 52062 Aachen, Germany
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3
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Schultz M, Parker SL, Fernando MT, Wellalage MM, Thomas DA. Diserinol Isophthalamide: A Novel Reagent for Complexation with Biomolecular Anions in Electrospray Ionization Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:745-753. [PMID: 36975839 DOI: 10.1021/jasms.3c00010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Transferring biomolecules from solution to vacuum facilitates a detailed analysis of molecular structure and dynamics by isolating molecules of interest from a complex environment. However, inherent in the ion desolvation process is the loss of solvent hydrogen bonding partners, which are critical for the stability of a condensed-phase structure. Thus, transfer of ions to vacuum can favor structural rearrangement, especially near solvent-accessible charge sites, which tend to adopt intramolecular hydrogen bonding motifs in the absence of solvent. Complexation of monoalkylammonium moieties (e.g., lysine side chains) with crown ethers such as 18-crown-6 can disfavor structural rearrangement of protonated sites, but no equivalent ligand has been investigated for deprotonated groups. Herein we describe diserinol isophthalamide (DIP), a novel reagent for the gas-phase complexation of anionic moieties within biomolecules. Complexation is observed to the C-terminus or side chains of the small model peptides GD, GE, GG, DF-OMe, VYV, YGGFL, and EYMPME in electrospray ionization mass spectrometry (ESI-MS) studies. In addition, complexation is observed with the phosphate and carboxylate moieities of phosphoserine and phosphotyrosine. DIP performs favorably in comparison to an existing anion recognition reagent, 1,1'-(1,2-phenylene)bis(3-phenylurea), that exhibits moderate carboxylate binding in organic solvent. This improved performance in ESI-MS experiments is attributed to reduced steric constraints to complexation with carboxylate groups of larger molecules. Overall, diserinol isophthalamide is an effective complexation reagent that can be applied in future work to study retention of solution-phase structure, investigate intrinsic molecular properties, and examine solvation effects.
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Affiliation(s)
- Madeline Schultz
- Department of Chemistry, University of Rhode Island, Kingston, Rhode Island 02881, United States
| | - Sarah L Parker
- Department of Chemistry, University of Rhode Island, Kingston, Rhode Island 02881, United States
| | - Maleesha T Fernando
- Department of Chemistry, University of Rhode Island, Kingston, Rhode Island 02881, United States
| | - Miyuru M Wellalage
- Department of Chemistry, University of Rhode Island, Kingston, Rhode Island 02881, United States
| | - Daniel A Thomas
- Department of Chemistry, University of Rhode Island, Kingston, Rhode Island 02881, United States
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Fouka M, Mavroeidi P, Tsaka G, Xilouri M. In Search of Effective Treatments Targeting α-Synuclein Toxicity in Synucleinopathies: Pros and Cons. Front Cell Dev Biol 2020; 8:559791. [PMID: 33015057 PMCID: PMC7500083 DOI: 10.3389/fcell.2020.559791] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 08/14/2020] [Indexed: 12/11/2022] Open
Abstract
Parkinson's disease (PD), multiple system atrophy (MSA) and Dementia with Lewy bodies (DLB) represent pathologically similar, progressive neurodegenerative disorders characterized by the pathological aggregation of the neuronal protein α-synuclein. PD and DLB are characterized by the abnormal accumulation and aggregation of α-synuclein in proteinaceous inclusions within neurons named Lewy bodies (LBs) and Lewy neurites (LNs), whereas in MSA α-synuclein inclusions are mainly detected within oligodendrocytes named glial cytoplasmic inclusions (GCIs). The presence of pathologically aggregated α-synuclein along with components of the protein degradation machinery, such as ubiquitin and p62, in LBs and GCIs is considered to underlie the pathogenic cascade that eventually leads to the severe neurodegeneration and neuroinflammation that characterizes these diseases. Importantly, α-synuclein is proposed to undergo pathogenic misfolding and oligomerization into higher-order structures, revealing self-templating conformations, and to exert the ability of "prion-like" spreading between cells. Therefore, the manner in which the protein is produced, is modified within neural cells and is degraded, represents a major focus of current research efforts in the field. Given that α-synuclein protein load is critical to disease pathogenesis, the identification of means to limit intracellular protein burden and halt α-synuclein propagation represents an obvious therapeutic approach in synucleinopathies. However, up to date the development of effective therapeutic strategies to prevent degeneration in synucleinopathies is limited, due to the lack of knowledge regarding the precise mechanisms underlying the observed pathology. This review critically summarizes the recent developed strategies to counteract α-synuclein toxicity, including those aimed to increase protein degradation, to prevent protein aggregation and cell-to-cell propagation, or to engage antibodies against α-synuclein and discuss open questions and unknowns for future therapeutic approaches.
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Affiliation(s)
| | | | | | - Maria Xilouri
- Center of Clinical Research, Experimental Surgery and Translational Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
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5
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Ikenaka K, Suzuki M, Mochizuki H, Nagai Y. Lipids as Trans-Acting Effectors for α-Synuclein in the Pathogenesis of Parkinson's Disease. Front Neurosci 2019; 13:693. [PMID: 31333408 PMCID: PMC6619337 DOI: 10.3389/fnins.2019.00693] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 06/18/2019] [Indexed: 12/15/2022] Open
Abstract
Aggregation of α-synuclein (αSyn) plays a central role in the pathogenesis of Parkinson’s disease (PD) and dementia with Lewy bodies (DLB). Lewy bodies (LBs) and Lewy neurites, which consist mainly of aggregated αSyn, are widely observed in the affected regions of patient brains. Except for some familial forms of PD/DLB, most sporadic PD/DLB patients express the wild-type (WT) αSyn protein without any mutations, and the mechanisms as to how WT αSyn gains the propensity to pathologically aggregate still remains unclear. Furthermore, the mechanisms by which the same αSyn protein can cause different synucleinopathies with distinct phenotypes and pathologies, such as PD, DLB, and multiple system atrophy (MSA), still remain largely unknown. Recently, mutations in the GBA1 gene (encoding glucocerebrosidase), which are responsible for the lysosomal storage disorder Gaucher disease (GD), have been reported to be the strongest risk factor for developing sporadic PD/DLB. We previously demonstrated that glucosylceramide accumulated by GBA1 deficiency promotes the conversion of αSyn into a proteinase K-resistant conformation. Furthermore, decreased glucocerebrosidase activity has also been reported in the brains of patients with sporadic PD/DLB. Moreover, αSyn pathology has also been shown in the brains of lysosomal storage disorder patients, which show glycosphingolipid accumulation. These observations suggest the possibility that altered lipid metabolism and lipid accumulation play roles in αSyn aggregation and PD/DLB pathogenesis. Indeed, several previous studies have demonstrated that lipid interactions affect the conformation of αSyn and induces its oligomerization and aggregation. In this review, we will give an overview of the association between αSyn aggregation and lipid interactions from the viewpoints of the etiology, pathology, and genetics of PD/DLB. We also discuss the distinct species of αSyn aggregates and their association with specific types of synucleinopathies, and introduce our hypothesis that lipid interactions play a role as trans-acting effectors in producing distinct strains of αSyn fibrils.
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Affiliation(s)
- Kensuke Ikenaka
- Department of Neurology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Mari Suzuki
- Department of Neurotherapeutics, Graduate School of Medicine, Osaka University, Osaka, Japan.,Diabetic Neuropathy Project, Department of Sensory and Motor Systems, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Hideki Mochizuki
- Department of Neurology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Yoshitaka Nagai
- Department of Neurology, Graduate School of Medicine, Osaka University, Osaka, Japan.,Department of Neurotherapeutics, Graduate School of Medicine, Osaka University, Osaka, Japan
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6
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McNary CP, Nei YW, Maitre P, Rodgers MT, Armentrout PB. Infrared multiple photon dissociation action spectroscopy of protonated glycine, histidine, lysine, and arginine complexed with 18-crown-6 ether. Phys Chem Chem Phys 2019; 21:12625-12639. [PMID: 31155616 DOI: 10.1039/c9cp02265a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Complexes of 18-crown-6 ether (18C6) with four protonated amino acids (AAs) are examined using infrared multiple photon dissociation (IRMPD) action spectroscopy utilizing light generated by the infrared free electron laser at the Centre Laser Infrarouge d'Orsay (CLIO). The AAs examined in this work include glycine (Gly) and the three basic AAs: histidine (His), lysine (Lys), and arginine (Arg). To identify the (AA)H+(18C6) conformations present in the experimental studies, the measured IRMPD spectra are compared to spectra calculated at the B3LYP/6-311+G(d,p) level of theory. Relative energies of various conformers and isomers are provided by single point energy calculations carried out at the B3LYP, B3P86, M06, and MP2(full) levels using the 6-311+G(2p,2d) basis set. The comparisons between the IRMPD and theoretical IR spectra indicate that 18C6 binds to Gly and His via the protonated backbone amino group, whereas protonated Lys prefers binding via the protonated side-chain amino group. Results for Arg are less definitive with strong evidence for binding to the protonated guanidino side chain (the calculated ground conformer at most levels of theory), but contributions from backbone binding to a zwitterionic structure are likely.
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Affiliation(s)
- Christopher P McNary
- Department of Chemistry, University of Utah, 315 S. 1400 E. Room 2020, Salt Lake City, Utah 84112, USA.
| | - Y-W Nei
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA.
| | - Philippe Maitre
- Université Paris Sud, Laboratoire de Chimie Physique, UMR8000 CNRS, Faculté des Sciences, Bâtiment 350, 91405 Orsay Cedex, France
| | - M T Rodgers
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA.
| | - P B Armentrout
- Department of Chemistry, University of Utah, 315 S. 1400 E. Room 2020, Salt Lake City, Utah 84112, USA.
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7
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Kelley AR, Colley ME, Perry G, Bach SBH. Incubation with Cu(II) and Zn(II) salts enhances MALDI-TOF mass spectra of amyloid-beta and α-synuclein toward in vivo analysis. JOURNAL OF MASS SPECTROMETRY : JMS 2018; 53:162-171. [PMID: 29111606 DOI: 10.1002/jms.4044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 10/18/2017] [Accepted: 10/23/2017] [Indexed: 06/07/2023]
Abstract
Insoluble senile plaque aggregates are indicative of Alzheimer's disease pathology. A similar phenomenon occurs in Parkinson's disease with the build-up of Lewy bodies. The analysis of senile plaques, and other brain samples, from Alzheimer's disease and Parkinson's disease patients by matrix-assisted laser desorption/ionization mass spectrometry has advantages but also presents obstacles because of the nature of the processes utilized in isolation procedures and storage. Salts, buffers, and detergents necessary in the isolation of biological species may cause adducts and ion suppression that convolute the spectra obtained. We previously determined that amyloid-beta from isolated senile plaque deposits fragment similarly to the synthetic 40 and 42 amino acid peptide when analyzed by matrix-assisted laser desorption/ionization mass spectrometry. In addition, α-synuclein also fragments predictably by in-source decay. This provides information that may be applied to the identification and localization of amyloid-beta and α-synuclein in senile plaques and intact tissue sections. Ion suppression must still be accounted for when analyzing biological samples, which makes identifying fragments at lower abundance difficult. The addition of certain transition-metal salts (Cu(II), Zn(II)) to the sample prior to analysis serves to "clean" the spectra and allow the peptide fragments produced to be observed with a much higher signal to noise and occasionally, improved resolution. We present a systematic study of incubation with different metal salts and their impact on the quality of the spectra, as well as the role of the binding of the metals to the model biological compounds, obtained for synthetic amyloid-beta, synthetic α-synuclein, and isolated senile plaques. The optimized sample preparation methods presented will provide for simpler and more thorough identification of these biologically relevant species in human-derived samples.
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Affiliation(s)
- Andrea R Kelley
- Department of Chemistry, University of Texas at San Antonio, One UTSA Blvd., San Antonio, TX, USA
| | - Madeline E Colley
- Department of Chemistry, University of Texas at San Antonio, One UTSA Blvd., San Antonio, TX, USA
| | - George Perry
- Department of Chemistry, University of Texas at San Antonio, One UTSA Blvd., San Antonio, TX, USA
| | - Stephan B H Bach
- Department of Chemistry, University of Texas at San Antonio, One UTSA Blvd., San Antonio, TX, USA
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8
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Lipstein N, Göth M, Piotrowski C, Pagel K, Sinz A, Jahn O. Presynaptic Calmodulin targets: lessons from structural proteomics. Expert Rev Proteomics 2017; 14:223-242. [DOI: 10.1080/14789450.2017.1275966] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Noa Lipstein
- Department of Molecular Neurobiology, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
| | - Melanie Göth
- Institute of Chemistry and Biochemistry, Free University Berlin, Berlin & Fritz Haber Institute of the Max-Planck-Society, Berlin, Germany
| | - Christine Piotrowski
- Department of Pharmaceutical Chemistry & Bioanalytics, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Kevin Pagel
- Institute of Chemistry and Biochemistry, Free University Berlin, Berlin & Fritz Haber Institute of the Max-Planck-Society, Berlin, Germany
| | - Andrea Sinz
- Department of Pharmaceutical Chemistry & Bioanalytics, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Olaf Jahn
- Proteomics Group, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
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9
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Susa AC, Xia Z, Tang HYH, Tainer JA, Williams ER. Charging of Proteins in Native Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:332-340. [PMID: 27734326 PMCID: PMC5283922 DOI: 10.1007/s13361-016-1517-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 09/22/2016] [Accepted: 09/27/2016] [Indexed: 05/19/2023]
Abstract
Factors that influence the charging of protein ions formed by electrospray ionization from aqueous solutions in which proteins have native structures and function were investigated. Protein ions ranging in molecular weight from 12.3 to 79.7 kDa and pI values from 5.4 to 9.6 were formed from different solutions and reacted with volatile bases of gas-phase basicities higher than that of ammonia in the cell of a Fourier-transform ion cyclotron resonance mass spectrometer. The charge-state distribution of cytochrome c ions formed from aqueous ammonium or potassium acetate is the same. Moreover, ions formed from these two solutions do not undergo proton transfer to 2-fluoropyridine, which is 8 kcal/mol more basic than ammonia. These results provide compelling evidence that proton transfer between ammonia and protein ions does not limit protein ion charge in native electrospray ionization. Both circular dichroism and ion mobility measurements indicate that there are differences in conformations of proteins in pure water and aqueous ammonium acetate, and these differences can account for the difference in the extent of charging and proton-transfer reactivities of protein ions formed from these solutions. The extent of proton transfer of the protein ions with higher gas-phase basicity bases trends with how closely the protein ions are charged to the value predicted by the Rayleigh limit for spherical water droplets approximately the same size as the proteins. These results indicate that droplet charge limits protein ion charge in native mass spectrometry and are consistent with these ions being formed by the charged residue mechanism. Graphical Abstract ᅟ.
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Affiliation(s)
- Anna C Susa
- Department of Chemistry, University of California, Berkeley, CA, 94720-1460, USA
| | - Zijie Xia
- Department of Chemistry, University of California, Berkeley, CA, 94720-1460, USA
| | - Henry Y H Tang
- Department of Chemistry, University of California, Berkeley, CA, 94720-1460, USA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - John A Tainer
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX, 77030, USA
| | - Evan R Williams
- Department of Chemistry, University of California, Berkeley, CA, 94720-1460, USA.
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10
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Going CC, Xia Z, Williams ER. Real-time HD Exchange Kinetics of Proteins from Buffered Aqueous Solution with Electrothermal Supercharging and Top-Down Tandem Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2016; 27:1019-1027. [PMID: 26919868 PMCID: PMC4865425 DOI: 10.1007/s13361-016-1350-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 01/21/2016] [Accepted: 01/22/2016] [Indexed: 06/05/2023]
Abstract
Electrothermal supercharging (ETS) with electrospray ionization produces highly charged protein ions from buffered aqueous solutions in which proteins have native folded structures. ETS increases the charge of ribonuclease A by 34%, whereas only a 6% increase in charge occurs for a reduced-alkylated form of this protein, which is unfolded and its structure is ~66% random coil in this solution. These results indicate that protein denaturation that occurs in the ESI droplets is the primary mechanism for ETS. ETS does not affect the extent of solution-phase hydrogen-deuterium exchange (HDX) that occurs for four proteins that have significantly different structures in solution, consistent with a droplet lifetime that is considerably shorter than observable rates of HDX. Rate constants for HDX of ubiquitin are obtained with a spatial resolution of ~1.3 residues with ETS and electron transfer dissociation of the 10+ charge-state using a single capillary containing a few μL of protein solution in which HDX continuously occurs. HDX protection at individual residues with ETS HDX is similar to that with reagent supercharging HDX and with solution-phase NMR, indicating that the high spray potentials required to induce ETS do not lead to HD scrambling. Graphical Abstract ᅟ.
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Affiliation(s)
- Catherine C Going
- Department of Chemistry, University of California, Berkeley, CA, 94720-1460, USA
| | - Zijie Xia
- Department of Chemistry, University of California, Berkeley, CA, 94720-1460, USA
| | - Evan R Williams
- Department of Chemistry, University of California, Berkeley, CA, 94720-1460, USA.
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11
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Emamzadeh FN. Alpha-synuclein structure, functions, and interactions. JOURNAL OF RESEARCH IN MEDICAL SCIENCES : THE OFFICIAL JOURNAL OF ISFAHAN UNIVERSITY OF MEDICAL SCIENCES 2016; 21:29. [PMID: 27904575 PMCID: PMC5122110 DOI: 10.4103/1735-1995.181989] [Citation(s) in RCA: 158] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2015] [Revised: 01/03/2016] [Accepted: 02/24/2016] [Indexed: 12/01/2022]
Abstract
At present, when a clinical diagnosis of Parkinson's disease (PD) is made, serious damage has already been done to nerve cells of the substantia nigra pars compacta. The diagnosis of PD in its earlier stages, before this irreversible damage, would be of enormous benefit for future treatment strategies designed to slow or halt the progression of this disease that possibly prevents accumulation of toxic aggregates. As a molecular biomarker for the detection of PD in its earlier stages, alpha-synuclein (α-syn), which is a key component of Lewy bodies, in which it is found in an aggregated and fibrillar form, has attracted considerable attention. Here, α-syn is reviewed in details.
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Affiliation(s)
- Fatemeh Nouri Emamzadeh
- Division of Biomedical and Life Sciences, Faculty of Health and Medicine, University of Lancaster, Lancaster, LA1 4AY, UK
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12
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Göth M, Lermyte F, Schmitt XJ, Warnke S, von Helden G, Sobott F, Pagel K. Gas-phase microsolvation of ubiquitin: investigation of crown ether complexation sites using ion mobility-mass spectrometry. Analyst 2016; 141:5502-10. [DOI: 10.1039/c6an01377e] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The influence of side chain to backbone interactions on the gas-phase structure of ubiquitin and ubiquitin lysine-to-arginine mutants was analysed.
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Affiliation(s)
- Melanie Göth
- Department of Biology
- Chemistry
- Pharmacy
- Freie Universität Berlin
- 14195 Berlin
| | - Frederik Lermyte
- Biomolecular and Analytical Mass Spectrometry
- Chemistry Department
- University of Antwerp
- 2020 Antwerp
- Belgium
| | - Xiao Jakob Schmitt
- Department of Molecular Physics
- Fritz Haber Institute of the Max Planck Society
- 14195 Berlin
- Germany
| | - Stephan Warnke
- Department of Molecular Physics
- Fritz Haber Institute of the Max Planck Society
- 14195 Berlin
- Germany
| | - Gert von Helden
- Department of Molecular Physics
- Fritz Haber Institute of the Max Planck Society
- 14195 Berlin
- Germany
| | - Frank Sobott
- Biomolecular and Analytical Mass Spectrometry
- Chemistry Department
- University of Antwerp
- 2020 Antwerp
- Belgium
| | - Kevin Pagel
- Department of Biology
- Chemistry
- Pharmacy
- Freie Universität Berlin
- 14195 Berlin
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13
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Hendricks NG, Julian RR. Characterizing gaseous peptide structure with action-EET and simulated annealing. Phys Chem Chem Phys 2015; 17:25822-7. [DOI: 10.1039/c5cp01617g] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Distance-sensitive energy transfer and molecular dynamics are used to generate experimentally corroborated structures for peptides in the gas phase.
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Affiliation(s)
| | - Ryan R. Julian
- Department of Chemistry
- University of California
- Riverside
- USA
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14
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Tian Y, Zhang X, Li Y, Shoup TM, Teng X, Elmaleh DR, Moore A, Ran C. Crown ethers attenuate aggregation of amyloid beta of Alzheimer's disease. Chem Commun (Camb) 2014; 50:15792-5. [PMID: 25372154 DOI: 10.1039/c4cc06029f] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this report, we reasoned that non-covalent modification of amyloid beta (Aβ) by crown ethers could inhibit its aggregation. We demonstrated that PiB-C, a conjugate PiB and crown ether, could significantly reduce the aggregation in vitro. Additionally, two-photon imaging showed that PiB-C could efficiently label Aβ plaques and CAAs in AD mice.
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Affiliation(s)
- Yanli Tian
- Molecular Imaging Laboratory, A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Building 75, Charlestown, Massachusetts 02129, USA.
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15
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Lee CC, Maestre-Reyna M, Hsu KC, Wang HC, Liu CI, Jeng WY, Lin LL, Wood R, Chou CC, Yang JM, Wang AHJ. Crowning proteins: modulating the protein surface properties using crown ethers. Angew Chem Int Ed Engl 2014; 53:13054-8. [PMID: 25287606 PMCID: PMC4288931 DOI: 10.1002/anie.201405664] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 07/16/2014] [Indexed: 11/18/2022]
Abstract
Crown ethers are small, cyclic polyethers that have found wide-spread use in phase-transfer catalysis and, to a certain degree, in protein chemistry. Crown ethers readily bind metallic and organic cations, including positively charged amino acid side chains. We elucidated the crystal structures of several protein-crown ether co-crystals grown in the presence of 18-crown-6. We then employed biophysical methods and molecular dynamics simulations to compare these complexes with the corresponding apoproteins and with similar complexes with ring-shaped low-molecular-weight polyethylene glycols. Our studies show that crown ethers can modify protein surface behavior dramatically by stabilizing either intra- or intermolecular interactions. Consequently, we propose that crown ethers can be used to modulate a wide variety of protein surface behaviors, such as oligomerization, domain–domain interactions, stabilization in organic solvents, and crystallization.
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Affiliation(s)
- Cheng-Chung Lee
- Institute of Biological Chemistry, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529 (Taiwan); Core Facilities for Protein Structural Analysis, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei 11529 (Taiwan)
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16
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Lee CC, Maestre-Reyna M, Hsu KC, Wang HC, Liu CI, Jeng WY, Lin LL, Wood R, Chou CC, Yang JM, Wang AHJ. Crowning Proteins: Modulating the Protein Surface Properties using Crown Ethers. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201405664] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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17
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Susa AC, Mortensen DN, Williams ER. Effects of cations on protein and peptide charging in electrospray ionization from aqueous solutions. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2014; 25:918-27. [PMID: 24729190 PMCID: PMC4051497 DOI: 10.1007/s13361-014-0864-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 02/12/2014] [Accepted: 02/18/2014] [Indexed: 05/11/2023]
Abstract
The effects of eight different cations with ionic radii between 69 and 337 pm on the charging of peptides and proteins with electrospray ionization from aqueous acetate salt solutions are reported. Significant adduction occurs for all cations except NH4(+), and the average protein charge is lower when formed from solutions containing salts compared with solutions without salts added. Circular dichroism and ion mobility results show the protein conformations are different in pure water compared with salt solutions, which likely affects the extent of charging. The average charge of protein and peptide ions formed from solutions with Li(+) and Cs(+), which have Gibbs solvation free energies (GSFEs) that differ by 225 kJ/mol, is similar. Lower charge states are typically formed from solutions with tetramethylammonium and tetraethylammonium that have lower GSFE values. Loss of the larger cations that have the lowest GSFEs is facile when adducted protein ions are collisionally activated, resulting in the formation of lower analyte charge states. This reaction pathway provides a route to produce abundant singly protonated protein ions under native mass spectrometry conditions. The average protein and peptide charge with NH4(+) is nearly the same as that with Rb(+) and K(+), cations with similar GSFE and ionic radii. This indicates that proton transfer from NH4(+) to proteins plays an insignificant role in the extent of protein charging in native mass spectrometry.
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Affiliation(s)
| | | | - Evan R. Williams
- Address correspondence to Prof. Evan R. Williams: Department of Chemistry, University of California, Berkeley, B42 Hildebrand Hall Berkeley, CA 94720, Phone: (510) 643-7161,
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18
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Flick TG, Merenbloom SI, Williams ER. Effects of metal ion adduction on the gas-phase conformations of protein ions. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2013; 24:1654-62. [PMID: 23733259 PMCID: PMC3795793 DOI: 10.1007/s13361-013-0664-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 04/10/2013] [Accepted: 05/03/2013] [Indexed: 05/16/2023]
Abstract
Changes in protein ion conformation as a result of nonspecific adduction of metal ions to the protein during electrospray ionization (ESI) from aqueous solutions were investigated using traveling wave ion mobility spectrometry (TWIMS). For all proteins examined, protein cations (and in most cases anions) with nonspecific metal ion adducts are more compact than the fully protonated (or deprotonated) ions with the same charge state. Compaction of protein cations upon nonspecific metal ion binding is most significant for intermediate charge state ions, and there is a greater reduction in collisional cross section with increasing number of metal ion adducts and increasing ion valency, consistent with an electrostatic interaction between the ions and the protein. Protein cations with the greatest number of adducted metal ions are no more compact than the lowest protonated ions formed from aqueous solutions. These results show that smaller collisional cross sections for metal-attached protein ions are not a good indicator of a specific metal-protein interaction in solution because nonspecific metal ion adduction also results in smaller gaseous protein cation cross sections. In contrast, the collisional cross section of α-lactalbumin, which specifically binds one Ca(2+), is larger for the holo-form compared with the apo-form, in agreement with solution-phase measurements. Because compaction of protein cations occurs when metal ion adduction is nonspecific, elongation of a protein cation may be a more reliable indicator that a specific metal ion-protein interaction occurs in solution.
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Affiliation(s)
| | | | - Evan R. Williams
- Address reprint requests to Prof. Evan R. Williams: Department of Chemistry University of California, Berkeley Latimer Hall #1460 Berkeley, CA 94620-1460 Phone: (510) 643-7161 Fax: (510) 542-7714
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19
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Zhou Y, Vachet RW. Covalent labeling with isotopically encoded reagents for faster structural analysis of proteins by mass spectrometry. Anal Chem 2013; 85:9664-70. [PMID: 24010814 DOI: 10.1021/ac401978w] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Covalent labeling and mass spectrometry (MS) are increasingly being used to obtain higher-order structure of proteins and protein complexes. Because most covalent labels are relatively large, steps must be taken to ensure the structural integrity of the modified protein during the labeling reactions so that correct structural information can be obtained. Measuring labeling kinetics is a reliable way to ensure that a given labeling reagent does not perturb a protein's structure, but obtaining such kinetic information is time and sample intensive because it requires multiple liquid chromatography (LC)-MS experiments. Here we present a new strategy that uses isotopically encoded labeling reagents to measure labeling kinetics in a single LC-MS experiment. We illustrate this new strategy by labeling solvent-exposed lysine residues with commercially available tandem mass tags. After tandem MS experiments, these tags allow the simultaneous identification of modified sites and determination of the reaction rates at each site in a way that is just as reliable as experiments that involve multiple LC-MS measurements.
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Affiliation(s)
- Yuping Zhou
- Department of Chemistry, University of Massachusetts , Amherst, Massachusetts 01003, United States
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20
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Moore BN, Hamdy O, Julian RR. Protein structure evolution in liquid DESI as revealed by selective noncovalent adduct protein probing. INTERNATIONAL JOURNAL OF MASS SPECTROMETRY 2012; 330-332:220-225. [PMID: 23526115 PMCID: PMC3601934 DOI: 10.1016/j.ijms.2012.08.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Previous experiments based on charge state distributions have suggested that liquid desorption electrospray ionization (DESI) is capable of preserving solution phase protein structure during transfer to the gas phase (Journal of the American Society for Mass Spectrometry 21 (2010) 1730-1736). In order to examine this possibility more carefully, we have utilized selective non-covalent adduct protein probing (SNAPP) to evaluate protein structural evolution in both liquid DESI and standard ESI under a variety of conditions. Experiments with cytochrome c (Cytc) demonstrated that methanol induced conformational shifts previously observed with ESI are also easily observed with liquid DESI. However, undesirable acid-induced unfolding becomes apparent at very high concentrations of methanol in liquid DESI due to acetic acid in the spray solvent, suggesting that there are conditions under which liquid DESI will not preserve solution phase structure. The effects of ammonium acetate buffer on liquid DESI SNAPP experiments were examined by monitoring structural changes in myoglobin. Heme retention and SNAPP distributions were both preserved better in liquid DESI than traditional ESI, suggesting superior performance for liquid DESI in buffered conditions. Finally, liquid DESI SNAPP was used to study the natively disordered proteins α, β, and γ synuclein with SNAPP. α-Synuclein, the main component of fibrils found in patients with Parkinson's disease, yielded a significantly different SNAPP distribution compared to β and γ synuclein. This difference is indicative of highly accessible protonated basic side chains, a property known to promote fibril formation in proteins.
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Affiliation(s)
| | | | - Ryan R. Julian
- Corresponding author. Tel.: +1 951 827 3958. (R.R. Julian)
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21
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Chen Y, Rodgers MT. Structural and energetic effects in the molecular recognition of acetylated amino acids by 18-crown-6. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2012; 23:2020-2030. [PMID: 22926972 DOI: 10.1007/s13361-012-0466-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 07/25/2012] [Accepted: 07/31/2012] [Indexed: 06/01/2023]
Abstract
Absolute 18-crown-6 (18C6) binding affinities of four protonated acetylated amino acids (AcAAs) are determined using guided ion beam tandem mass spectrometry techniques. The AcAAs examined in this work include: N-terminal acetylated lysine (N(α)-AcLys), histidine (N(α)-AcHis), and arginine (N(α)-AcArg) as well as side chain acetylated lysine (N(ε)-AcLys). The kinetic-energy-dependent cross sections for collision-induced dissociation (CID) of the (AcAA)H(+)(18C6) complexes are analyzed using an empirical threshold law to extract absolute 0 and 298 K (AcAA)H(+)-18C6 bond dissociation energies (BDEs) after accounting for the effects of multiple collisions, kinetic and internal energy distributions of the reactants, and unimolecular dissociation lifetimes. Theoretical electronic structure calculations are performed to determine stable geometries and energetics for neutral and protonated 18C6 and the AcAAs as well as the proton bound complexes of these species, (AcAA)H(+)(18C6), at the B3LYP/6-311+G(2d,2p)//B3LYP/6-31 G* and M06/6-311+G(2d,2p)//B3LYP/6-31G* levels of theory. For all four (AcAA)H(+)(18C6) complexes, loss of neutral 18C6 corresponds to the most favorable dissociation pathway. At elevated energies, products arising from sequential dissociation of the primary CID product, H(+)(AcAA), are also observed. Protonated N(α)-AcLys exhibits a greater 18C6 binding affinity than other protonated N(α)-AcAAs, suggesting that the side chains of Lys residues are the preferred binding sites for 18C6 complexation to peptides and proteins. N(α)-AcLys exhibits a greater 18C6 binding affinity than N(ε)-AcLys, suggesting that binding of 18C6 to the side chain of Lys residues is more favorable than to the N-terminal amino group of Lys.
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Affiliation(s)
- Yu Chen
- Department of Chemistry, Wayne State University, Detroit, MI 48202, USA
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22
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Faller P, Hureau C, Dorlet P, Hellwig P, Coppel Y, Collin F, Alies B. Methods and techniques to study the bioinorganic chemistry of metal–peptide complexes linked to neurodegenerative diseases. Coord Chem Rev 2012. [DOI: 10.1016/j.ccr.2012.03.015] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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23
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24
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Grasso G, Spoto G. Plasmonics for the study of metal ion–protein interactions. Anal Bioanal Chem 2012; 405:1833-43. [DOI: 10.1007/s00216-012-6421-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 09/10/2012] [Accepted: 09/12/2012] [Indexed: 12/19/2022]
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25
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Stedwell CN, Galindo JF, Gulyuz K, Roitberg AE, Polfer NC. Crown Complexation of Protonated Amino Acids: Influence on IRMPD Spectra. J Phys Chem A 2012; 117:1181-8. [DOI: 10.1021/jp305263b] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Corey N. Stedwell
- Department of Chemistry
and Center for Chemical Physics, University of Florida, Gainesville, P.O. Box 117200, Florida 32611-7200,
United States
| | - Johan F. Galindo
- Department of Chemistry
and Quantum Theory Project, University of Florida, Gainesville, P.O. Box 118435, Florida 32611-8435,
United States
| | - Kerim Gulyuz
- Department of Chemistry
and Center for Chemical Physics, University of Florida, Gainesville, P.O. Box 117200, Florida 32611-7200,
United States
| | - Adrian E. Roitberg
- Department of Chemistry
and Quantum Theory Project, University of Florida, Gainesville, P.O. Box 118435, Florida 32611-8435,
United States
| | - Nicolas C. Polfer
- Department of Chemistry
and Center for Chemical Physics, University of Florida, Gainesville, P.O. Box 117200, Florida 32611-7200,
United States
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26
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Chen Y, Rodgers MT. Re-Evaluation of the Proton Affinity of 18-Crown-6 Using Competitive Threshold Collision-Induced Dissociation Techniques. Anal Chem 2012; 84:7570-7. [DOI: 10.1021/ac301804j] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yu Chen
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - M. T. Rodgers
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
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27
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Zhou Y, Vachet RW. Diethylpyrocarbonate labeling for the structural analysis of proteins: label scrambling in solution and how to avoid it. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2012; 23:899-907. [PMID: 22351293 PMCID: PMC3324597 DOI: 10.1007/s13361-012-0349-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 01/20/2012] [Accepted: 01/23/2012] [Indexed: 05/11/2023]
Abstract
Covalent labeling along with mass spectrometry is a method that is increasingly used to study protein structure. Recently, it has been shown that diethylpyrocarbonate (DEPC) is a powerful labeling reagent because it can modify up to 30% of the residues in the average protein, including the N-terminus, His, Lys, Tyr, Ser, Thr, and Cys residues. We recently discovered, however, that Cys residues that form disulfide bonds appear to be modified by DEPC as well. In this work, we demonstrate that disulfide linked Cys residues are not actually reactive with DEPC but, instead, once reduced, free Cys residues can capture a carbethoxy group from other modified amino acids via a solution-phase reaction that can occur during the protein digestion step. This "scrambling" of carbethoxy groups decreases the amount of modification observed at other residues and can potentially provide incorrect protein structural information. Fortunately, label scrambling can be completely avoided by alkylating the free thiols after disulfide reduction.
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Affiliation(s)
| | - Richard W. Vachet
- Corresponding Author, Department of Chemistry, LGRT 104, 710 N. Pleasant St., University of Massachusetts, Amherst, MA 01003,
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28
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Zhou Y, Vachet RW. Increased protein structural resolution from diethylpyrocarbonate-based covalent labeling and mass spectrometric detection. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2012; 23:708-17. [PMID: 22298289 PMCID: PMC3334416 DOI: 10.1007/s13361-011-0332-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 12/21/2011] [Accepted: 12/28/2011] [Indexed: 05/03/2023]
Abstract
Covalent labeling and mass spectrometry are seeing increased use together as a way to obtain insight into the 3-dimensional structure of proteins and protein complexes. Several amino acid specific (e.g., diethylpyrocarbonate) and non-specific (e.g., hydroxyl radicals) labeling reagents are available for this purpose. Diethylpyrocarbonate (DEPC) is a promising labeling reagent because it can potentially probe up to 30% of the residues in the average protein and gives only one reaction product, thereby facilitating mass spectrometric analysis. It was recently reported, though, that DEPC modifications are labile for some amino acids. Here, we show that label loss is more significant and widespread than previously thought, especially for Ser, Thr, Tyr, and His residues, when relatively long protein digestion times are used. Such label loss ultimately decreases the amount of protein structural information that is obtainable with this reagent. We find, however, that the number of DEPC modified residues and, thus, protein structural information, can be significantly increased by decreasing the time between the covalent labeling reaction and the mass spectrometric analysis. This is most effectively accomplished using short (e.g., 2 h) proteolytic digestions with enzymes such as immobilized chymotrypsin or Glu-C rather than using methods (e.g., microwave or ultrasonic irradiation) that accelerate proteolysis in other ways. Using short digestion times, we show that the percentage of solvent accessible residues that can be modified by DEPC increases from 44% to 67% for cytochrome c, 35% to 81% for myoglobin, and 76% to 95% for β-2-microglobulin. In effect, these increased numbers of modified residues improve the protein structural resolution available from this covalent labeling method. Compared with typical overnight digestion conditions, the short digestion times decrease the average distance between modified residues from 11 to 7 Å for myoglobin, 13 to 10 Å for cytochrome c, and 9 to 8 Å for β-2-microglobulin.
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Affiliation(s)
| | - Richard W. Vachet
- Corresponding Author: Department of Chemistry, LGRT 104, 710 N. Pleasant St., University of Massachusetts, Amherst, MA 01003,
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29
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Chen Y, Rodgers MT. Structural and Energetic Effects in the Molecular Recognition of Amino Acids by 18-Crown-6. J Am Chem Soc 2012; 134:5863-75. [DOI: 10.1021/ja211021h] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Yu Chen
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - M. T. Rodgers
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
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30
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Tao Y, Julian RR. Examining protein surface structure in highly conserved sequence variants with mass spectrometry. Biochemistry 2012; 51:1796-802. [PMID: 22320248 DOI: 10.1021/bi2018199] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A simple mass spectrometry-based method capable of examining protein structure called SNAPP (selective noncovalent adduct protein probing) is used to evaluate the structural consequences of point mutations in naturally occurring sequence variants from different species. SNAPP monitors changes in the attachment of noncovalent adducts to proteins as a function of structural state. Mutations that lead to perturbations to the electrostatic surface structure of a protein affect noncovalent attachment and are easily observed with SNAPP. Mutations that do not alter the tertiary structure or electrostatic surface structure yield similar results by SNAPP. For example, bovine, porcine, and human insulin all have very similar backbone structures and no basic or acidic residue mutations, and the SNAPP distributions for all three proteins are very similar. In contrast, four variants of cytochrome c (cytc) have varying degrees of sequence homology, which are reflected in the observed SNAPP distributions. Bovine and pigeon cytc have several basic or acidic residue substitutions relative to horse cytc, but the SNAPP distributions for all three proteins are similar. This suggests that these mutations do not significantly influence the protein surface structure. On the other hand, yeast cytc has the least sequence homology and exhibits a unique, though related, SNAPP distribution. Even greater differences are observed for lysozyme. Hen and human lysozyme have identical tertiary structures but significant variations in the locations of numerous basic and acidic residues. The SNAPP distributions are quite distinct for the two forms of lysozyme, suggesting significant differences in the surface structures. In summary, SNAPP experiments are relatively easy to perform, require minimal sample consumption, and provide a facile route for comparison of protein surface structure between highly homologous proteins.
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Affiliation(s)
- Yuanqi Tao
- Department of Chemistry, University of California, Riverside, California 92521, United States
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31
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Percy AJ, Rey M, Burns KM, Schriemer DC. Probing protein interactions with hydrogen/deuterium exchange and mass spectrometry-a review. Anal Chim Acta 2012; 721:7-21. [PMID: 22405295 DOI: 10.1016/j.aca.2012.01.037] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Revised: 01/13/2012] [Accepted: 01/17/2012] [Indexed: 11/17/2022]
Abstract
Assessing the functional outcome of protein interactions in structural terms is a goal of structural biology, however most techniques have a limited capacity for making structure-function determinations with both high resolution and high throughput. Mass spectrometry can be applied as a reader of protein chemistries in order to fill this void, and enable methodologies whereby protein structure-function determinations may be made on a proteome-wide level. Protein hydrogen/deuterium exchange (H/DX) offers a chemical labeling strategy suitable for tracking changes in "dynamic topography" and thus represents a powerful means of monitoring protein structure-function relationships. This review presents the exchange method in the context of interaction analysis. Applications involving interface detection, quantitation of binding, and conformational responses to ligation are discussed, and commentary on recent analytical developments is provided.
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Affiliation(s)
- Andrew J Percy
- Department of Chemistry, University of Calgary, Alberta, Canada
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32
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Chen Y, Rodgers MT. Structural and Energetic Effects in the Molecular Recognition of Protonated Peptidomimetic Bases by 18-Crown-6. J Am Chem Soc 2012; 134:2313-24. [DOI: 10.1021/ja2102345] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yu Chen
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
| | - M. T. Rodgers
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, United States
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33
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Structural characterization of Cu2+, Ni2+ and Zn2+ binding sites of model peptides associated with neurodegenerative diseases. Coord Chem Rev 2012. [DOI: 10.1016/j.ccr.2011.07.004] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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34
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Calabrese AN, Speechley LA, Pukala TL. Characterisation of Calmodulin Structural Transitions by Ion Mobility Mass Spectrometry. Aust J Chem 2012. [DOI: 10.1071/ch12047] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
This study demonstrates the ability of travelling wave ion mobility-mass spectrometry to measure collision cross-sections of ions in the negative mode, using a calibration based approach. Here, negative mode ion mobility-mass spectrometry was utilised to understand structural transitions of calmodulin upon Ca2+ binding and complexation with model peptides melittin and the plasma membrane Ca2+ pump C20W peptide. Coexisting calmodulin conformers were distinguished on the basis of their mass and cross-section, and identified as relatively folded and unfolded populations, with good agreement in collision cross-section to known calmodulin geometries. Titration of calcium tartrate to physiologically relevant Ca2+ levels provided evidence for intermediately metalated species during the transition from apo- to holo-calmodulin, with collision cross-section measurements indicating that higher Ca2+ occupancy is correlated with more compact structures. The binding of two representative peptides which exemplify canonical compact (melittin) and extended (C20W) peptide-calmodulin binding models has also been interrogated by ion mobility mass spectrometry. Peptide binding to calmodulin involves intermediates with metalation states from 1–4 Ca2+, which demonstrate relatively collapsed structures, suggesting neither the existence of holo-calmodulin or a pre-folded calmodulin conformation is a prerequisite for binding target peptides or proteins. The biological importance of the different metal unsaturated calmodulin complexes, if any, is yet to be understood.
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35
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Hamdy OM, Julian RR. Reflections on charge state distributions, protein structure, and the mystical mechanism of electrospray ionization. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2012; 23:1-6. [PMID: 22076632 DOI: 10.1007/s13361-011-0284-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2011] [Revised: 10/18/2011] [Accepted: 10/19/2011] [Indexed: 05/31/2023]
Abstract
The connection between charge state distributions, protein structure, and mechanistic details of electrospray are discussed in relation to the emerging field of gas phase structural biology. Comparisons are drawn with the established area of enzymatic catalysis in organic solvents, which shares many similar challenges. Charge solvation emerges as a dominant force in both systems that must be dealt with to enable kinetic trapping of native structures in foreign environments. Potential methods for mediating unfavorable charge solvation effects are discussed and, ironically, do not include partial solvation by water. The importance of timescale in relation to the evolution of protein structure during the process of electrospray ionization is discussed. Finally several prospects for future endeavors are highlighted.
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36
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Breydo L, Wu JW, Uversky VN. Α-synuclein misfolding and Parkinson's disease. Biochim Biophys Acta Mol Basis Dis 2011; 1822:261-85. [PMID: 22024360 DOI: 10.1016/j.bbadis.2011.10.002] [Citation(s) in RCA: 440] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Revised: 08/26/2011] [Accepted: 10/03/2011] [Indexed: 12/21/2022]
Abstract
Substantial evidence links α-synuclein, a small highly conserved presynaptic protein with unknown function, to both familial and sporadic Parkinson's disease (PD). α-Synuclein has been identified as the major component of Lewy bodies and Lewy neurites, the characteristic proteinaceous deposits that are the hallmarks of PD. α-Synuclein is a typical intrinsically disordered protein, but can adopt a number of different conformational states depending on conditions and cofactors. These include the helical membrane-bound form, a partially-folded state that is a key intermediate in aggregation and fibrillation, various oligomeric species, and fibrillar and amorphous aggregates. The molecular basis of PD appears to be tightly coupled to the aggregation of α-synuclein and the factors that affect its conformation. This review examines the different aggregation states of α-synuclein, the molecular mechanism of its aggregation, and the influence of environmental and genetic factors on this process.
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Affiliation(s)
- Leonid Breydo
- Department of Molecular Medicine, College of Medicine, University of South Florida, Tampa, FL 33612, USA
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Sun Q, Tyler RC, Volkman BF, Julian RR. Dynamic interchanging native states of lymphotactin examined by SNAPP-MS. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2011; 22:399-407. [PMID: 21472559 PMCID: PMC3061006 DOI: 10.1007/s13361-010-0042-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Revised: 11/15/2010] [Accepted: 11/15/2010] [Indexed: 05/30/2023]
Abstract
The human chemokine lymphotactin (Ltn) is a remarkable protein that interconverts between two unrelated native state structures in the condensed phase. It is possible to shift the equilibrium toward either conformation with selected sequence substitutions. Previous results have shown that a disulfide-stabilized variant preferentially adopts the canonical chemokine fold (Ltn10), while a single amino acid change (W55D) favors the novel Ltn40 dimeric structure. Selective noncovalent adduct protein probing (SNAPP) is a recently developed method for examining solution phase protein structure. Herein, it is demonstrated that SNAPP can easily recognize and distinguish between the Ltn10 and Ltn40 states of lymphotactin in aqueous solution. The effects of organic denaturants, acid, and disulfide bond reduction and blocking were also examined using SNAPP for the CC3, W55D, and wild type proteins. Only disulfide reduction was shown to significantly perturb the protein, and resulted in considerably decreased adduct formation consistent with loss of tertiary/secondary structure. Cold denaturation experiments demonstrated that wild-type Ltn is the most temperature sensitive of the three proteins. Examination of the higher charge states in all experiments, which are presumed to represent transition state structures between Ltn-10 and Ltn-40, reveals increased 18C6 attachment relative to the more folded structures. This observation is consistent with increased competitive intramolecular hydrogen bonding, which may guide the transition. Experiments examining the gas phase structures revealed that all three proteins can be structurally distinguished in the gas phase. In addition, the gas phase experiments enabled identification of preferred adduct binding sites.
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Affiliation(s)
- Qingyu Sun
- Department of Chemistry, University of California, Riverside, CA 92521 USA
| | - Robert C. Tyler
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226 USA
| | - Brian F. Volkman
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226 USA
| | - Ryan R. Julian
- Department of Chemistry, University of California, Riverside, CA 92521 USA
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Flick TG, Merenbloom SI, Williams ER. A simple and robust method for determining the number of basic sites in peptides and proteins using electrospray ionization mass spectrometry. Anal Chem 2011; 83:2210-4. [PMID: 21338067 DOI: 10.1021/ac1031012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A solution additive has been discovered that can be used to measure the number of basic sites in a peptide or protein using electrospray ionization (ESI) mass spectrometry. Addition of millimolar amounts of perchloric acid (HClO(4)) to aqueous solutions that contain peptides or proteins results in the noncovalent adduction of HClO(4) molecules to the multiply charged ions formed by ESI. For 18 oligopeptides and proteins, ranging in molecular weight from 0.5 to 18.3 kDa, the sum of the number of protons plus maximum number of HClO(4) molecules adducted to the lower charge state ions is equal to the number of basic sites in the molecule. This method provides a rapid means of obtaining information about the composition of a peptide or protein and does not require high-resolution measurements or any instrumental or experimental modifications.
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Affiliation(s)
- Tawnya G Flick
- Department of Chemistry, University of California, Berkeley, California 94720-1460, United States
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Qu C, Yu S, Bai A, Wang J. Study on the interactions between ginsenosides and lysozyme under acidic condition by ESI-MS and molecular docking. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2011; 78:676-680. [PMID: 21183401 DOI: 10.1016/j.saa.2010.11.047] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 10/28/2010] [Accepted: 11/30/2010] [Indexed: 05/30/2023]
Abstract
In order to study the different effects of ginsenosides with similar structures, research on interactions between ginsenoside Rg1, Re and lysozyme was carried out by electrospray ionization mass spectrometry (ESI-MS) and molecular docking. The 1:1 and 2:1 noncovalent complexes of ginsenosides and lysozyme were observed in the mass spectra and the dissociation constants for them were directly calculated based on peak intensities of lysozyme and its noncovalent complexes with ginsenosides. The results showed that the 1:1 complex of ginsenoside Rg1 and lysozyme was more stable than that of ginsenoside Re and lysozyme. As the acidity increased, the stabilities of the 1:1 complexes of Rg1, Re and lysozyme both decreased. Interestingly, as the acidity increased, the stability of the 2:1 complex of Rg1 and lysozyme increased while that of Re decreased. From the result of molecular docking, ginsenosides interacted with the active sites of lysozyme. And the stability of the complexes could be affected by the conformation changes of lysozyme as acidity increased.
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Affiliation(s)
- Chenling Qu
- College of Grain Oil and Food Science, Henan University of Technology, 140 Songshan South Road, Zhengzhou 450052, China.
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Valensin D, Camponeschi F, Luczkowski M, Baratto MC, Remelli M, Valensin G, Kozlowski H. The role of His-50 of α-synuclein in binding Cu(ii): pH dependence, speciation, thermodynamics and structure. Metallomics 2011; 3:292-302. [DOI: 10.1039/c0mt00068j] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Angel LA. Study of metal ion labeling of the conformational and charge states of lysozyme by ion mobility mass spectrometry. EUROPEAN JOURNAL OF MASS SPECTROMETRY (CHICHESTER, ENGLAND) 2011; 17:207-215. [PMID: 21828412 DOI: 10.1255/ejms.1133] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The efficiency of Zn(2+), Cu(2+), Ni(2+), Co(2+), Fe(2+) or Mn(2+) labeling of the conformational and charge states of lysozyme was studied in H(2)O solvent at pH 2.5-6.8. Labeling of lysozyme was conducted with 50 M, 100 M and 500 M excess of the metal ion, resulting in the number of metal ions attached to lysozyme increasing two-fold over this range. At pH 6.2-6.8, Zn(2+), Cu(2+), Ni(2+), Co(2+) and Mn(2+) labeled the highly folded 7+ conformer and the 8+ and 9+ partially unfolded conformers of lysozyme with the same number of metal ion tags, with only Fe(2+) exhibiting no labeling. Lysozyme conserved its charge after metal ion labeling which shows at each charge state the divalent metal ion is replacing two protons. As the pH is lowered to 4.7-5.0 and 2.5-2.9, the labeling of lysozyme by Zn(2+), Cu(2+), Ni(2+), Co(2+) or Mn(2+) decreased in efficiency due to increased competition from protons for the aspartate and glutamate binding sites. The metal ions preferentially labeled the highly folded 7+ and partially unfolded 8+ conformers, but labeling decreased as the charge of lysozyme increased. In contrast to the other metal ions, Fe(2+) exhibited labeling of lysozyme only at the lowest pH of 2.8. At higher pH, the oxidation of Fe(2+) and formation of hydroxy-bridged complexes probably make the Fe(2+) unreactive towards lysozyme.
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Affiliation(s)
- Laurence A Angel
- Texas A&M University-Commerce, Department of Chemistry, PO Box 3011, Commerce, TX 75429-3011, USA.
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Pan J, Konermann L. Calcium-Induced Structural Transitions of the Calmodulin−Melittin System Studied by Electrospray Mass Spectrometry: Conformational Subpopulations and Metal-Unsaturated Intermediates. Biochemistry 2010; 49:3477-86. [DOI: 10.1021/bi100261c] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Jingxi Pan
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
| | - Lars Konermann
- Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5B7, Canada
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Frimpong AK, Abzalimov RR, Uversky VN, Kaltashov IA. Characterization of intrinsically disordered proteins with electrospray ionization mass spectrometry: conformational heterogeneity of alpha-synuclein. Proteins 2010; 78:714-22. [PMID: 19847913 DOI: 10.1002/prot.22604] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Conformational heterogeneity of alpha-synuclein was studied with electrospray ionization mass spectrometry by analyzing protein ion charge state distributions, where the extent of multiple charging reflects compactness of the protein conformations in solution. Although alpha-synuclein lacks a single well-defined structure under physiological conditions, it was found to sample four distinct conformational states, ranging from a highly structured one to a random coil. The compact highly structured state of alpha-synuclein is present across the entire range of conditions tested (pH ranging from 2.5 to 10, alcohol content from 0% to 60%), but is particularly abundant in acidic solutions. The only other protein state populated in acidic solutions is a partially folded intermediate state lacking stable tertiary structure. Another, more compact intermediate state is induced by significant amounts of ethanol used as a co-solvent and appears to represent a partially folded conformation with high beta-sheet content. Protein dimerization is observed throughout the entire range of conditions tested, although only acidic solutions favor formation of highly structured dimers of alpha-synuclein. These dimers are likely to present the earliest stages in protein aggregation leading to globular oligomers and, subsequently, protofibrils.
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Affiliation(s)
- Agya K Frimpong
- Department of Chemistry, University of Massachusetts Amherst, Amherst, MA 01003, USA
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Santner A, Uversky VN. Metalloproteomics and metal toxicology of α-synuclein. Metallomics 2010; 2:378-92. [DOI: 10.1039/b926659c] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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