1
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Wu HT, Van Orman BL, Julian RR. Localizing Isomerized Residue Sites in Peptides with Tandem Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2024; 35:705-713. [PMID: 38440975 PMCID: PMC10995990 DOI: 10.1021/jasms.3c00373] [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] [Received: 10/25/2023] [Revised: 02/22/2024] [Accepted: 02/26/2024] [Indexed: 03/06/2024]
Abstract
Isomerized amino acid residues have been identified in many peptides extracted from tissues or excretions of humans and animals. These isomerized residues can play key roles by affecting biological activity or by exerting an influence on the process of aging. Isomerization occurs spontaneously and does not result in a mass shift. Thus, identifying and localizing isomerized residues in biological samples is challenging. Herein, we introduce a fast and efficient method using tandem mass spectrometry (MS) to locate isomerized residues in peptides. Although MS2 spectra are useful for identifying peptides that contain an isomerized residue, they cannot reliably localize isomerization sites. We show that this limitation can be overcome by utilizing MS3 experiments to further evaluate each fragment ion from the MS2 stage. Comparison at the MS3 level, utilizing statistical analyses, reveals which MS2 fragments differ between samples and, therefore, must contain the isomerized sites. The approach is similar to previous work relying on ion mobility to discriminate MS2 product ions by collision cross-section. The MS3 approach can be implemented using either ion-trap or beam-type collisional activation and is compatible with the quantification of isomer mixtures when coupled to a calibration curve. The method can also be implemented in combination with liquid chromatography in a targeted approach. Enabling the identification and localization of isomerized residues in peptides with an MS-only methodology will expand accessibility to this important information.
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Affiliation(s)
- Hoi-Ting Wu
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Brielle L. Van Orman
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Ryan R. Julian
- Department of Chemistry, University of California, Riverside, California 92521, United States
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2
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Chen J, Fasihianifard P, Raz AAP, Hickey BL, Moreno JL, Chang CEA, Hooley RJ, Zhong W. Selective recognition and discrimination of single isomeric changes in peptide strands with a host : guest sensing array. Chem Sci 2024; 15:1885-1893. [PMID: 38303931 PMCID: PMC10829040 DOI: 10.1039/d3sc06087j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 12/30/2023] [Indexed: 02/03/2024] Open
Abstract
An indirect competitive binding mechanism can be exploited to allow a combination of cationic fluorophores and water-soluble synthetic receptors to selectively recognize and discriminate peptide strands containing a single isomeric residue in the backbone. Peptide isomerization occurs in long-lived proteins and has been linked with diseases such as Alzheimer's, cataracts and cancer, so isomers are valuable yet underexplored targets for selective recognition. Planar cationic fluorophores can selectively bind hydrophobic, Trp-containing peptide strands in solution, and when paired with receptors that provide a competitive host for the fluorophore, can form a differential sensing array that enables selective discrimination of peptide isomers. Residue variations such as D- and L-Asp, D- and L-isoAsp, D-Ser and D-Glu can all be recognized, simply by their effects on the folded structure of the flexible peptide. Molecular dynamics simulations were applied to determine the most favorable conformation of the peptide : fluorophore conjugate, indicating that favorable π-stacking with internal tryptophan residues in a folded binding pocket enables micromolar binding affinity.
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Affiliation(s)
- Junyi Chen
- Environmental Toxicology Graduate Program, University of California-Riverside Riverside CA 92521 USA
| | - Parisa Fasihianifard
- Department of Chemistry, University of California-Riverside Riverside CA 92521 USA
| | - Alexie Andrea P Raz
- Department of Chemistry, University of California-Riverside Riverside CA 92521 USA
| | - Briana L Hickey
- Department of Chemistry, University of California-Riverside Riverside CA 92521 USA
| | - Jose L Moreno
- Department of Chemistry, University of California-Riverside Riverside CA 92521 USA
| | - Chia-En A Chang
- Department of Chemistry, University of California-Riverside Riverside CA 92521 USA
| | - Richard J Hooley
- Department of Chemistry, University of California-Riverside Riverside CA 92521 USA
- Environmental Toxicology Graduate Program, University of California-Riverside Riverside CA 92521 USA
| | - Wenwan Zhong
- Department of Chemistry, University of California-Riverside Riverside CA 92521 USA
- Environmental Toxicology Graduate Program, University of California-Riverside Riverside CA 92521 USA
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3
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Readel ER, Dhaubhadel U, Patel A, Armstrong DW. Variable fragmentation and ionization of amyloid-beta epimers and isomers. Anal Bioanal Chem 2023; 415:6799-6807. [PMID: 37787853 DOI: 10.1007/s00216-023-04958-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 08/25/2023] [Accepted: 09/12/2023] [Indexed: 10/04/2023]
Abstract
While the existence of D-amino acids in peptides and proteins has recently been accepted in higher forms of life, their roles and importance are yet to be understood. The lack of analytical methods present for such epimeric and/or isomeric analyses often limits developments in the field. Studies have shown the elevated presence of epimeric and isomeric modifications to amyloid-beta (Aβ) peptides extracted from Alzheimer's disease patients. These modifications most frequently occur through aspartic acid and serine residues. Because such peptides are indistinguishable by mass alone, selective liquid chromatography tandem mass spectrometry analysis is required to differentiate such peptides. Herein, we examine MS/MS of tryptic fragments of Aβ peptides containing D-Asp, L-iso-Asp, D-iso-Asp, and/or D-Ser modifications. Peptide ionizability and fragmentation are explored through selected reaction monitoring, selected ion monitoring, and product ion scan. The results show the variability of ionization and fragmentation for many "identical mass peptides" and how these differences can affect the analysis of isomeric and epimeric peptides.
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Affiliation(s)
- Elizabeth R Readel
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, 76019, USA
| | - Umang Dhaubhadel
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, 76019, USA
| | - Arzoo Patel
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, 76019, USA
| | - Daniel W Armstrong
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, 76019, USA.
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4
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Bashyal A, Hui JO, Flick T, Dykstra AB, Zhang Q, Campuzano IDG, Brodbelt JS. Differentiation of Aspartic and Isoaspartic Acid Using 193 nm Ultraviolet Photodissociation Mass Spectrometry. Anal Chem 2023; 95:11510-11517. [PMID: 37458293 PMCID: PMC10588209 DOI: 10.1021/acs.analchem.3c02025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2023]
Abstract
Spontaneous conversion of aspartic acid (Asp) to isoaspartic acid (isoAsp) is a ubiquitous modification that influences the structure and function of proteins. This modification of Asp impacts the stability of biotherapeutics and has been linked to the development of neurodegenerative diseases. We explored the use of 193 nm ultraviolet photodissociation (UVPD) to distinguish Asp and isoAsp in the protonated and deprotonated peptides. The differences in the relative abundances of several fragment ions uniquely generated by UVPD were used to differentiate isomeric peptide standards containing Asp or isoAsp. These fragment ions result from the cleavage of bonds N-terminal to Asp/isoAsp residues in addition to the side-chain losses from Asp/isoAsp or the losses of COOH, CO2, CO, or H2O from y-ions. Fragmentation of Asp-containing tryptic peptides using UVPD resulted in more enhanced w/w + 1/y - 1/x ions, while isoAsp-containing peptides yielded more enhanced y - 18/y - 45/y - 46 ions. UVPD was also used to identify an isomerized peptide from a tryptic digest of a monoclonal antibody. Moreover, UVPD of a protonated nontryptic peptide resulted in more enhanced y ions N- and C-terminal to isoAsp and differences in b/y ion ratios that were used to identify the isoAsp peptide.
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Affiliation(s)
- Aarti Bashyal
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - John O Hui
- Amgen Research, Molecular Analytics, Amgen Inc., Thousand Oaks, California 91320, United States
| | - Tawnya Flick
- Process Development, Attribute Sciences, Amgen Inc., Thousand Oaks, California 91320, United States
| | - Andrew B Dykstra
- Process Development, Attribute Sciences, Amgen Inc., Thousand Oaks, California 91320, United States
| | - Qingchun Zhang
- Process Development, Attribute Sciences, Amgen Inc., Thousand Oaks, California 91320, United States
| | - Iain D G Campuzano
- Amgen Research, Molecular Analytics, Amgen Inc., Thousand Oaks, California 91320, United States
| | - Jennifer S Brodbelt
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
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5
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Yussif BM, Blasing CV, Checco JW. Endogenous l- to d-amino acid residue isomerization modulates selectivity between distinct neuropeptide receptor family members. Proc Natl Acad Sci U S A 2023; 120:e2217604120. [PMID: 36877849 PMCID: PMC10089201 DOI: 10.1073/pnas.2217604120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 02/03/2023] [Indexed: 03/08/2023] Open
Abstract
The l- to d-amino acid residue isomerization of neuropeptides is an understudied post-translational modification found in animals across several phyla. Despite its physiological importance, little information is available regarding the impact of endogenous peptide isomerization on receptor recognition and activation. As a result, the full roles peptide isomerization play in biology are not well understood. Here, we identify that the Aplysia allatotropin-related peptide (ATRP) signaling system utilizes l- to d-residue isomerization of one amino acid residue in the neuropeptide ligand to modulate selectivity between two distinct G protein-coupled receptors (GPCRs). We first identified a novel receptor for ATRP that is selective for the D2-ATRP form, which bears a single d-phenylalanine residue at position 2. Using cell-based receptor activation experiments, we then characterized the stereoselectivity of the two known ATRP receptors for both endogenous ATRP diastereomers, as well as for homologous toxin peptides from a carnivorous predator. We found that the ATRP system displayed dual signaling through both the Gαq and Gαs pathways, and each receptor was selectively activated by one naturally occurring ligand diastereomer over the other. Overall, our results provide insights into an unexplored mechanism by which nature regulates intercellular communication. Given the challenges in detecting l- to d-residue isomerization from complex mixtures de novo and in identifying receptors for novel neuropeptides, it is likely that other neuropeptide-receptor systems may also utilize changes in stereochemistry to modulate receptor selectivity in a manner similar to that discovered here.
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Affiliation(s)
- Baba M. Yussif
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE68588
| | - Cole V. Blasing
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE68588
| | - James W. Checco
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE68588
- The Nebraska Center for Integrated Biomolecular Communication, University of Nebraska-Lincoln, Lincoln, NE68588
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6
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Xu X, Han L, Zheng Z, Zhao R, Li L, Shao X, Li G. Composite Multidimensional Ion Mobility-Mass Spectrometry for Improved Differentiation of Stereochemical Modifications. Anal Chem 2023; 95:2221-2228. [PMID: 36635260 DOI: 10.1021/acs.analchem.2c03522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Stereochemical modifications (SCMs), mostly present in the form of d-amino acid substitution, have been increasingly identified from a wide range of neuropeptides and disease-associated biomarker proteins. Traditional mass spectrometry-based SCM identification has been effectively enhanced with technological and strategic advancements in ion mobility spectrometry. With the additional separation provided by ion mobility, SCM-induced structural changes can be probed both in theory and in practice, although the structural resolution for low-abundance SCMs still requires further improvement to enable accurate quantification or unambiguous identification of stereoisomers. Herein, we present a multi-component-enabled multidimensional ion mobility-mass spectrometry (3M-IM-MS) analytical workflow, based upon the metal-enhanced chiral amplification strategy we proposed previously (Nat. Commun., 2019, 5038). Notably, the 3M-IM-MS strategy comprises and features the powerful mathematical tools of continuous wavelet transform and Gaussian fitting-enabled peak splitting. Consequently, the resolving capability of ion mobility spectrometry for SCM analysis has been significantly enhanced, providing mobility profiles with baseline separation and more than fivefold improvement in resolving power and overall resolution. This study represents an alternative toward ultrahigh-resolution structural interrogation of mixtures with very small differences, featuring an important and long-lasting topic in chemical measurement.
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Affiliation(s)
- Xia Xu
- Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Science, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Li Han
- Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Science, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Zhen Zheng
- School of Pharmacy, Tianjin Medical University, Tianjin 300070, China
| | - Rui Zhao
- Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Science, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Lingjun Li
- School of Pharmacy and Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53705, United States
| | - Xueguang Shao
- Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Science, College of Chemistry, Nankai University, Tianjin 300071, China.,Haihe Laboratory of Sustainable Chemical Transformations, Tianjin 300192, China
| | - Gongyu Li
- Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Science, College of Chemistry, Nankai University, Tianjin 300071, China.,Haihe Laboratory of Sustainable Chemical Transformations, Tianjin 300192, China
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7
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Moi S, Shekh S, Dolle A, Vijayasarathy M, Gowd KH. Significance of D- tryptophan in Contryphan-Ar1131 Conus peptide: Oxidative folding, trypsin binding, and photostabilization activity. Peptides 2022; 156:170845. [PMID: 35902005 DOI: 10.1016/j.peptides.2022.170845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 07/06/2022] [Accepted: 07/23/2022] [Indexed: 11/28/2022]
Abstract
Distinct differences have been observed between L-tryptophan and D-tryptophan containing contryphan-Ar1131 in oxidative folding, trypsin binding, and photostabilization activity on avobenzone. [W5] contryphan-Ar1131 and [w5] contryphan-Ar1131 were chemically synthesized and characterized using RP-HPLC and mass spectrometry. Structural differences due to the change of configuration of tryptophan were evident from the optimized structures of contryphan-Ar1131 using density functional theory (DFT). The comparison of early events of oxidative folding has revealed the role of D-tryptophan in accelerating the formation of a disulfide bond. The optimized structures of the reduced form of peptides revealed the occurrence of aromatic-aromatic and aromatic-proline interactions in [w5] contryphan-Ar1131 which may be critical in aiding the oxidative folding reaction. The presence of the Lys6-Pro7 peptide bond indicates that contryphan-Ar1131 is resistant but may bind to trypsin allowing to assign the binding affinity of peptides to the protein surface. Competitive binding studies and molecular docking along with molecular dynamic (MD) simulations have revealed that [w5] contryphan-Ar1131 has more affinity for the active site of trypsin. Given tryptophan is a photostabilizer of FDA-approved chemical UV-A filter avobenzone, the report has compared the photostabilization activity of [W5]/ [w5] contryphan-Ar1131 on avobenzone under natural sunlight. [w5] contryphan-Ar1131 has better photostabilization activity than that of [W5] contryphan-Ar1131 and also individual D-tryptophan and L-tryptophan amino acids. These biochemical studies have highlighted the significance of D-tryptophan in contryphan-Ar1131 and its photostabilization activity on avobenzone may find applications in cosmetics.
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Affiliation(s)
- Smriti Moi
- Department of Chemistry, School of Chemical Sciences, Central University of Karnataka, Kalaburagi 585367, Karnataka, India
| | - Shamasoddin Shekh
- Department of Chemistry, School of Chemical Sciences, Central University of Karnataka, Kalaburagi 585367, Karnataka, India
| | - Ashwini Dolle
- Department of Chemistry, School of Chemical Sciences, Central University of Karnataka, Kalaburagi 585367, Karnataka, India
| | | | - Konkallu Hanumae Gowd
- Department of Chemistry, School of Chemical Sciences, Central University of Karnataka, Kalaburagi 585367, Karnataka, India.
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8
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Lambeth TR, Julian RR. Efficient Isothiocyanate Modification of Peptides Facilitates Structural Analysis by Radical-Directed Dissociation. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:1338-1345. [PMID: 34670075 DOI: 10.1021/jasms.1c00237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Radical-directed dissociation (RDD) is a powerful technique for structural characterization of peptides in mass spectrometry experiments. Prior to analysis, a radical precursor must typically be appended to facilitate generation of a free radical. To explore the use of a radical precursor that can be easily attached in a single step, we modified peptides using a "click" reaction with iodophenyl isothiocyanate. Coupling with amine functional groups proceeds with high yields, producing stable iodophenylthiourea-modified peptides. Photodissociation yields were recorded at 266 and 213 nm for the 2-, 3-, and 4-iodo isomers of the modifier and found to be highest for the 4-iodo isomer in nearly all cases. Fragmentation of the modified peptides following collisional activation revealed favorable losses of the tag, and electronic structure calculations were used to evaluate a potential mechanism involving hydrogen transfer within the thiourea group. Examination of RDD data revealed that 4-iodobenzoic acid, 4-iodophenylthiourea, and 3-iodotyrosine yield similar fragmentation patterns for a given peptide, although differences in fragment abundance are noted. Iodophenyl isothiocyanate labeling in combination with RDD can be used to differentiate isomeric amino acids within peptides, which should facilitate simplified evaluation of isomers present in complex biological samples.
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Affiliation(s)
- Tyler R Lambeth
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Ryan R Julian
- Department of Chemistry, University of California, Riverside, California 92521, United States
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9
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Butler KE, Dodds JN, Flick T, Campuzano IDG, Baker ES. High-Resolution Demultiplexing (HRdm) Ion Mobility Spectrometry-Mass Spectrometry for Aspartic and Isoaspartic Acid Determination and Screening. Anal Chem 2022; 94:6191-6199. [PMID: 35421308 DOI: 10.1021/acs.analchem.1c05533] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Isomeric peptide analyses are an analytical challenge of great importance to therapeutic monoclonal antibody and other biotherapeutic product development workflows. Aspartic acid (Asp, D) to isoaspartic acid (isoAsp, isoD) isomerization is a critical quality attribute (CQA) that requires careful control, monitoring, and quantitation during the drug discovery and production processes. While the formation of isoAsp has been implicated in a variety of disease states such as autoimmune diseases and several types of cancer, it is also understood that the formation of isoAsp results in a structural change impacting efficacy, potency, and immunogenic properties, all of which are undesirable. Currently, lengthy ultrahigh-performance liquid chromatography (UPLC) separations are coupled with MS for CQA analyses; however, these measurements often take over an hour and drastically limit analysis throughput. In this manuscript, drift tube ion mobility spectrometry-mass spectrometry (DTIMS-MS) and both a standard and high-resolution demultiplexing approach were utilized to study eight isomeric Asp and isoAsp peptide pairs. While the limited resolving power associated with the standard DTIMS analysis only separated three of the eight pairs, the application of HRdm distinguished seven of the eight and was only unable to separate DL and isoDL. The rapid high-throughput HRdm DTIMS-MS method was also interfaced with both flow injection and an automated solid phase extraction system to present the first application of HRdm for isoAsp and Asp assessment and demonstrate screening capabilities for isomeric peptides in complex samples, resulting in a workflow highly suitable for biopharmaceutical research needs.
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Affiliation(s)
- Karen E Butler
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - James N Dodds
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Tawnya Flick
- Pivotal Attribute Sciences, Amgen Process Development, Thousand Oaks, California 91320, United States
| | - Iain D G Campuzano
- Discovery Attribute Sciences, Amgen Research, Thousand Oaks, California 91320, United States
| | - Erin S Baker
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695, United States.,Center for Human Health and the Environment, North Carolina State University, Raleigh, North Carolina 27695, United States.,Comparative Medicine Institute, North Carolina State University, Raleigh, North Carolina 27695, United States
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10
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Deamidation of the human eye lens protein γS-crystallin accelerates oxidative aging. Structure 2022; 30:763-776.e4. [PMID: 35338852 PMCID: PMC9081212 DOI: 10.1016/j.str.2022.03.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 12/14/2021] [Accepted: 03/01/2022] [Indexed: 11/23/2022]
Abstract
Cataract, a clouding of the eye lens from protein precipitation, affects millions of people every year. The lens proteins, the crystallins, show extensive post-translational modifications (PTMs) in cataractous lenses. The most common PTMs, deamidation and oxidation, promote crystallin aggregation; however, it is not clear precisely how these PTMs contribute to crystallin insolubilization. Here, we report six crystal structures of the lens protein γS-crystallin (γS): one of the wild-type and five of deamidated γS variants, from three to nine deamidation sites, after sample aging. The deamidation mutations do not change the overall fold of γS; however, increasing deamidation leads to accelerated disulfide-bond formation. Addition of deamidated sites progressively destabilized protein structure, and the deamidated variants display an increased propensity for aggregation. These results suggest that the deamidated variants are useful as models for accelerated aging; the structural changes observed provide support for redox activity of γS-crystallin in the lens.
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11
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Edwards HM, Wu HT, Julian RR, Jackson GP. Differentiating aspartic acid isomers and epimers with charge transfer dissociation mass spectrometry (CTD-MS). Analyst 2022; 147:1159-1168. [PMID: 35188507 DOI: 10.1039/d1an02279b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The ability to understand the function of a protein often relies on knowledge about its detailed structure. Sometimes, seemingly insignificant changes in the primary structure of a protein, like an amino acid substitution, can completely disrupt a protein's function. Long-lived proteins (LLPs), which can be found in critical areas of the human body, like the brain and eye, are especially susceptible to primary sequence alterations in the form of isomerization and epimerization. Because long-lived proteins do not have the corrective regeneration capabilities of most other proteins, points of isomerism and epimerization that accumulate within the proteins can severely hamper their functions and can lead to serious diseases like Alzheimer's disease, cancer and cataracts. Whereas tandem mass spectrometry (MS/MS) in the form of collision-induced dissociation (CID) generally excels at peptide characterization, MS/MS often struggles to pinpoint modifications within LLPs, especially when the differences are only isomeric or epimeric in nature. One of the most prevalent and difficult-to-identify modifications is that of aspartic acid between its four isomeric forms: L-Asp, L-isoAsp, D-Asp, and D-isoAsp. In this study, peptides containing isomers of Asp were analyzed by charge transfer dissociation (CTD) mass spectrometry to identify spectral features that could discriminate between the different isomers. For the four isomers of Asp in three model peptides, CTD produced diagnostic ions of the form cn+57 on the N-terminal side of iso-Asp residues, but not on the N-terminal side of Asp residues. Using CTD, the L- and D forms of Asp and isoAsp could also be differentiated based on the relative abundance of y- and z ions on the C-terminal side of Asp residues. Differentiation was accomplished through a chiral discrimination factor, R, which compares an ion ratio in a spectrum of one epimer or isomer to the same ion ratio in the spectrum of a different epimer or isomer. The R values obtained using CTD are as robust and statistically significant as other fragmentation techniques, like radical directed dissociation (RDD). In summary, the extent of backbone and side-chain fragments produced by CTD enabled the differentiation of isomers and epimers of Asp in a variety of peptides.
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Affiliation(s)
- Halle M Edwards
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, USA.
| | - Hoi-Ting Wu
- Department of Chemistry, University of California, Riverside, CA, USA
| | - Ryan R Julian
- Department of Chemistry, University of California, Riverside, CA, USA
| | - Glen P Jackson
- C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV, USA. .,Department of Forensic and Investigative Science, West Virginia University, Morgantown, WV, USA
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12
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Yussif BM, Checco JW. Evaluation of endogenous peptide stereochemistry using liquid chromatography-mass spectrometry-based spiking experiments. Methods Enzymol 2022; 663:205-234. [DOI: 10.1016/bs.mie.2021.10.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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13
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Tomczyk N, Giles K, Richardson K, Ujma J, Palmer M, Nielsen PK, Haselmann KF. Mapping Isomeric Peptides Derived from Biopharmaceuticals Using High-Resolution Ion Mobility Mass Spectrometry. Anal Chem 2021; 93:16379-16384. [PMID: 34842410 DOI: 10.1021/acs.analchem.1c02834] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The identification and localization of isomeric peptide modifications is a critical requirement of the biopharmaceutical industry. Despite the ability of liquid chromatography-mass spectrometry to identify many of the common post translational modifications, the identification of isobaric or racemized peptides is confounded by modern mass spectrometry-based techniques. Here, we present a novel approach combining liquid chromatography with a high-resolution ion mobility mass spectrometry system to differentiate peptide and peptide fragments based upon their mobility and mass.
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Affiliation(s)
- Nick Tomczyk
- Waters Corporation, Stamford Avenue, Wilmslow SK9 4AX, U.K
| | - Kevin Giles
- Waters Corporation, Stamford Avenue, Wilmslow SK9 4AX, U.K
| | | | - Jakub Ujma
- Waters Corporation, Stamford Avenue, Wilmslow SK9 4AX, U.K
| | - Martin Palmer
- Waters Corporation, Stamford Avenue, Wilmslow SK9 4AX, U.K
| | - Peter Kresten Nielsen
- Novo Nordisk A/S, Global Research Technologies, Novo Nordisk Park, Maaloev DK-2760, Denmark
| | - Kim F Haselmann
- Novo Nordisk A/S, Global Research Technologies, Novo Nordisk Park, Maaloev DK-2760, Denmark
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14
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Lian Z, Wang N, Tian Y, Huang L. Characterization of Synthetic Peptide Therapeutics Using Liquid Chromatography-Mass Spectrometry: Challenges, Solutions, Pitfalls, and Future Perspectives. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:1852-1860. [PMID: 34110145 DOI: 10.1021/jasms.0c00479] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Synthetic peptides represent an important and expanding class of therapeutics. Despite having a relatively small size as compared to monoclonal antibodies and other proteins, synthetic peptides are subject to many complex structural modifications originating from the starting materials, manufacturing process, and storage conditions. Although mass spectrometry has been increasingly used to characterize impurities of synthetic peptides, systematic review of this field is scarce. In this paper, an overview of the impurities in synthetic peptide therapeutics is provided in the context of how the knowledge from detailed characterization of the impurities using liquid chromatography-mass spectrometry (LC-MS) can be used to develop the manufacturing process and control strategy for synthetic peptide therapeutics following the critical quality attribute (CQA)-driven and risk-based approach. The thresholds for identifying and controlling the impurities are discussed based on currently available regulatory guidance. Specific LC-MS techniques for identification of various types of impurities based on their structural characteristics are discussed with the focus on structural isomers and stereoisomers (i.e., peptide epimers). Absolute and relative quantitation methods for the peptide impurities are critiqued. Potential pitfalls in characterization of synthetic peptide therapeutics using LC-MS are discussed. Finally, a systematic LC-MS workflow for characterizing the impurities in synthetic peptide therapeutics is proposed, and future perspectives on applying emerging LC-MS techniques to address the remaining challenges in the development of synthetic peptide therapeutics are presented.
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Affiliation(s)
- Zhirui Lian
- Bioproducts Research and Development, Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana 46285, United States
| | - Ning Wang
- Bioproducts Research and Development, Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana 46285, United States
| | - Yuwei Tian
- Bioproducts Research and Development, Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana 46285, United States
| | - Lihua Huang
- Bioproducts Research and Development, Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana 46285, United States
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15
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Readel ER, Wey M, Armstrong DW. Rapid and selective separation of amyloid beta from its stereoisomeric point mutations implicated in neurodegenerative Alzheimer's disease. Anal Chim Acta 2021; 1163:338506. [PMID: 34024415 DOI: 10.1016/j.aca.2021.338506] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 03/31/2021] [Accepted: 04/07/2021] [Indexed: 12/25/2022]
Abstract
Extracellular deposition of amyloid beta (Aβ) peptides are a hallmark of Alzheimer's disease. The isomerization and epimerization of Aβ peptides have been linked to the enhanced deposition of Aβ plaques. Therefore, considerable effort has been expended to create effective methods to distinguish such aberrant Aβ peptides from normal Aβ peptides. Herein, we have developed chromatographic retention U-shaped curves to investigate the hydrophobicity of Aβ 1-38, 1-40, 1-42 and fourteen aberrant Aβ 1-42 peptides. Using this information, we developed the first selective and comprehensive method that can easily detect both aberrant and normal Aβ peptides simultaneously using high performance liquid chromatography-mass spectrometry (HPLC-MS). We show for the first time that D-Ser modifications to Aβ cause the peptide to be more hydrophilic, as does D-Asp and L/D-iso-Asp.
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Affiliation(s)
- Elizabeth R Readel
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, 76019, USA
| | - Michael Wey
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, 76019, USA
| | - Daniel W Armstrong
- Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX, 76019, USA.
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16
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Cantrell LS, Schey KL. Proteomic characterization of the human lens and Cataractogenesis. Expert Rev Proteomics 2021; 18:119-135. [PMID: 33849365 DOI: 10.1080/14789450.2021.1913062] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
INTRODUCTION The goal of this review is to highlight the triumphs and frontiers in measurement of the lens proteome as it relates to onset of age-related nuclear cataract. As global life expectancy increases, so too does the frequency of age-related nuclear cataracts. Molecular therapeutics do not exist for delay or relief of cataract onset in humans. Since lens fiber cells are incapable of protein synthesis after initial maturation, age-related changes in proteome composition and post-translational modification accumulation can be measured with various techniques. Several of these modifications have been associated with cataract onset. AREAS COVERED We discuss the impact of long-lived proteins on the lens proteome and lens homeostasis as well as proteomic techniques that may be used to measure proteomes at various levels of proteomic specificity and spatial resolution. EXPERT OPINION There is clear evidence that several proteome modifications are correlated with cataract formation. Past studies should be enhanced with cutting-edge, spatially resolved mass spectrometry techniques to enhance the specificity and sensitivity of modification detection as it relates to cataract formation.
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Affiliation(s)
- Lee S Cantrell
- Department of Biochemistry, Vanderbilt University, Nashville, TN, United States
| | - Kevin L Schey
- Department of Biochemistry, Vanderbilt University, Nashville, TN, United States
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17
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Fujii N, Takata T, Kim I, Matsubara T. Simultaneous and Rapid Detection of Multiple Epimers and Isomers of Aspartyl Residues in Lens Proteins Using an LC-MS-MRM Method. ACS OMEGA 2020; 5:27626-27632. [PMID: 33134726 PMCID: PMC7594319 DOI: 10.1021/acsomega.0c04197] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 10/02/2020] [Indexed: 05/03/2023]
Abstract
Traditionally, studies of post translational modifications (PTMs) by mass analysis have been limited to modifications such as deamidation and oxidation that have a mass shift. Although Asp isomerization is an important PTM, the selective detection of Asp isomers by mass spectrometry was originally thought to be impossible due to the identical mass of the isomers. The recent development of an LC-MS-based method has facilitated rapid and accurate quantitative analysis of Asp isomers in long-lived proteins; however, because the quantification is based on the extracted ion chromatogram acquired by an MS1 scan, this methodology is not always efficient for detecting extremely low-abundance peptides in complex biological samples. In this paper, we evaluated Asp isomer-containing peptides of αA-crystallin present in tryptic digests of human lens samples with different degrees of protein aggregation and different ages using LC coupled with multiple reaction monitoring (MRM). In a single analysis, the LC-MRM method enabled three tryptic peptides containing isomers of Asp58, Asp91/92, and Asp151 to be detected simultaneously. The extent of isomerization and epimerization of these specific Asp sites in αA-crystallin increased with the progress of α-crystallin aggregation. For the analysis of samples known to isomerize at specific Asp residues, MRM gives a more rapid, less laborious, and high-quality separation of Asp isomer-containing peptides relative to the previous MS1-based quantitative method.
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Affiliation(s)
- Noriko Fujii
- Institute
for Integrated Radiation and Nuclear Science, Kyoto University, 2
Asashironishi, Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan
- . Tel.: +81-72-451-2496
| | - Takumi Takata
- Institute
for Integrated Radiation and Nuclear Science, Kyoto University, 2
Asashironishi, Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan
| | - Ingu Kim
- Institute
for Integrated Radiation and Nuclear Science, Kyoto University, 2
Asashironishi, Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan
| | - Toshiya Matsubara
- Shimadzu
Corporation, 1 Nisinokyo Kuwabara, Nakagyo-ku, Kyoto 604-8511, Japan
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18
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Murtada R, Fabijanczuk K, Gaspar K, Dong X, Alzarieni KZ, Calix K, Manriquez E, Bakestani RM, Kenttämaa HI, Gao J. Free-Radical-Mediated Glycan Isomer Differentiation. Anal Chem 2020; 92:13794-13802. [PMID: 32935980 DOI: 10.1021/acs.analchem.0c02213] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The inherent structural complexity and diversity of glycans pose a major analytical challenge to their structural analysis. Radical chemistry has gained considerable momentum in the field of mass spectrometric biomolecule analysis, including proteomics, glycomics, and lipidomics. Herein, seven isomeric disaccharides and two isomeric tetrasaccharides with subtle structural differences are distinguished rapidly and accurately via one-step radical-induced dissociation. The free-radical-activated glycan-sequencing reagent (FRAGS) selectively conjugates to the unique reducing terminus of glycans in which a localized nascent free radical is generated upon collisional activation and simultaneously induces glycan fragmentation. Higher-energy collisional dissociation (HCD) and collision-induced dissociation (CID) are employed to provide complementary structural information for the identification and discrimination of glycan isomers by providing different fragmentation pathways to generate informative, structurally significant product ions. Furthermore, multiple-stage tandem mass spectrometry (MS3 CID) provides supplementary and valuable structural information through the generation of characteristic parent-structure-dependent fragment ions.
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Affiliation(s)
- Rayan Murtada
- Department of Chemistry and Biochemistry, Montclair State University, 1 Normal Avenue, Montclair, New Jersey 07043, United States
| | - Kimberly Fabijanczuk
- Department of Chemistry and Biochemistry, Montclair State University, 1 Normal Avenue, Montclair, New Jersey 07043, United States
| | - Kaylee Gaspar
- Department of Chemistry and Biochemistry, Montclair State University, 1 Normal Avenue, Montclair, New Jersey 07043, United States
| | - Xueming Dong
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Kawthar Zeyad Alzarieni
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Kimberly Calix
- Department of Chemistry and Biochemistry, Montclair State University, 1 Normal Avenue, Montclair, New Jersey 07043, United States
| | - Edgar Manriquez
- Department of Chemistry and Biochemistry, Montclair State University, 1 Normal Avenue, Montclair, New Jersey 07043, United States
| | - Rose Mery Bakestani
- Department of Chemistry and Biochemistry, Montclair State University, 1 Normal Avenue, Montclair, New Jersey 07043, United States
| | - Hilkka I Kenttämaa
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907, United States
| | - Jinshan Gao
- Department of Chemistry and Biochemistry, Montclair State University, 1 Normal Avenue, Montclair, New Jersey 07043, United States
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19
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Silzel JW, Murphree TA, Paranji RK, Guttman MM, Julian RR. Probing the Stability of Proline Cis/Trans Isomers in the Gas Phase with Ultraviolet Photodissociation. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:1974-1980. [PMID: 32808771 DOI: 10.1021/jasms.0c00242] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Although most peptide bonds in proteins exist in the trans configuration, when cis peptide bonds do occur, they can have major impact on protein structure and function. The rapid identification of cis peptide bonds is therefore an important task. Peptide bonds containing proline are more likely to adopt the cis configuration because the ring connecting the side chain and backbone in proline flattens the energetic landscape relative to amino acids with free side chains. Examples of cis proline isomers have been identified in both solution and in the gas phase by a variety of structure-probing methods. Mass spectrometry is an attractive potential method for identifying cis proline due to its speed and sensitivity; however, the question remains of whether cis/trans proline isomers originating in solution are preserved during ionization and manipulation within a mass spectrometer. Herein, we investigate the gas-phase stability of isolated solution-phase cis and trans proline isomers using a synthetic peptide sequence with a Tyr-Pro-Pro motif. A variety of dissociation methods were explored to evaluate their potential to distinguish cis/trans configuration, including collision-induced dissociation, radical-directed dissociation, and photodissociation. Only photodissociation employed in conjunction with extremely gentle electrospray and charge solvation by 18-crown-6 ether was able to distinguish cis/trans isomers for our model peptide, suggesting that any thermal activation during transfer or while in the gas phase leads to isomer scrambling. Furthermore, the necessity for 18-crown-6 suggests that intramolecular charge solvation taking place during electrospray ionization can override cis/trans isomer homogeneity. Overall, the results suggest that solution-phase cis/trans proline isomers are fragile and easily lost during electrospray, requiring careful selection of instrument parameters and consideration of charge solvation to prevent cis/trans scrambling.
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Affiliation(s)
- Jacob W Silzel
- Department of Chemistry, University of California, 501 Big Springs Road, Riverside, California 92521, United States
| | - Taylor A Murphree
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Rajan K Paranji
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Miklos M Guttman
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Ryan R Julian
- Department of Chemistry, University of California, 501 Big Springs Road, Riverside, California 92521, United States
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20
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Wu HT, Julian RR. Two-dimensional identification and localization of isomers in crystallin peptides using TWIM-MS. Analyst 2020; 145:5232-5241. [PMID: 32608408 DOI: 10.1039/d0an01036g] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Recent studies have illuminated connections between spontaneous chemical reactions that cause isomerization at specific protein residues and various age-related diseases including cataracts and Alzheimer's. These discoveries provide impetus for better analytical methods to detect and characterize isomerization in proteins, which will enable a more complete understanding of the underlying relationship between these modifications and biology. Herein we employ a two-dimensional approach for identification of peptides isomers that also includes pinpointing of the modified residue. Collision-induced dissociation is used to fragment ions in the first dimension, followed by separation of the fragments with travelling-wave ion mobility. By comparing data obtained from both isomers, differences in either fragment-ion intensities or arrival-time distributions can be used to identify isomeric forms and the specific site of modification within the peptides. Synthetic peptide standards with sequences derived from long-lived proteins in the eye lens and isomerization at serine, aspartic acid, and glutamic acid were examined. Although both dimensions are capable of isomer identification, ion mobility is much better at determining the site of modification. In general, separation of isomeric forms by ion mobility is possible but does not follow predictable trends dictated by sequence or fragment-ion length. In most cases, however, the site of isomerization can be precisely determined.
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Affiliation(s)
- Hoi-Ting Wu
- Department of Chemistry, University of California, Riverside, California 92521, USA.
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21
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Ying Y, Li H. Recent progress in the analysis of protein deamidation using mass spectrometry. Methods 2020; 200:42-57. [PMID: 32544593 DOI: 10.1016/j.ymeth.2020.06.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 05/15/2020] [Accepted: 06/11/2020] [Indexed: 02/06/2023] Open
Abstract
Deamidation is a nonenzymatic and spontaneous posttranslational modification (PTM) that introduces changes in both structure and charge of proteins, strongly associated with aging proteome instability and degenerative diseases. Deamidation is also a common PTM occurring in biopharmaceutical proteins, representing a major cause of degradation. Therefore, characterization of deamidation alongside its inter-related modifications, isomerization and racemization, is critically important to understand their roles in protein stability and diseases. Mass spectrometry (MS) has become an indispensable tool in site-specific identification of PTMs for proteomics and structural studies. In this review, we focus on the recent advances of MS analysis in protein deamidation. In particular, we provide an update on sample preparation, chromatographic separation, and MS technologies at multi-level scales, for accurate and reliable characterization of protein deamidation in both simple and complex biological samples, yielding important new insight on how deamidation together with isomerization and racemization occurs. These technological progresses will lead to a better understanding of how deamidation contributes to the pathology of aging and other degenerative diseases and the development of biopharmaceutical drugs.
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Affiliation(s)
- Yujia Ying
- School of Pharmaceutical Sciences, University of Sun Yat-sen University, No.132 Wai Huan Dong Lu, Guangzhou Higher Education Mega Center, Guangzhou 510006, China; School of Pharmacy, China Pharmaceutical University, 639 Longmian Avenue, Nanjing 211198, China
| | - Huilin Li
- School of Pharmaceutical Sciences, University of Sun Yat-sen University, No.132 Wai Huan Dong Lu, Guangzhou Higher Education Mega Center, Guangzhou 510006, China; Guangdong Key Laboratory of Chiral Molecule and Drug Discovery, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, Guangdong 510006, China.
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22
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Fujii N, Takata T, Kim I, Morishima K, Inoue R, Magami K, Matsubara T, Sugiyama M, Koide T. Asp isomerization increases aggregation of α-crystallin and decreases its chaperone activity in human lens of various ages. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1868:140446. [PMID: 32442520 DOI: 10.1016/j.bbapap.2020.140446] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 05/12/2020] [Accepted: 05/14/2020] [Indexed: 10/24/2022]
Abstract
α-Crystallin, comprising 40-50 subunits of αA- and αB-subunits, is a long-lived major soluble chaperone protein in lens. During aging, α-crystallin forms aggregates of high molecular weight (HMW) protein and eventually becomes water-insoluble (WI). Isomerization of Asp in α-crystallin has been proposed as a trigger of protein aggregation, ultimately leading to cataract formation. Here, we have investigated the relationship between protein aggregation and Asp isomerization of αA-crystallin by a series of analyses of the soluble α-crystallin, HMW and WI fractions from human lens samples of different ages (10-76 years). Analytical ultracentrifugation showed that the HMW fraction had a peak sedimentation coefficient of 40 S and a wide distribution of values (10-450 S) for lens of all ages, whereas the α-crystallin had a much smaller peak sedimentation coefficient (10-20 S) and was less heterogeneous, regardless of lens age. Measurement of the ratio of isomers (Lα-, Lβ-, Dα-, Dβ-) at Asp58, Asp91/92 and Asp151 in αA-crystallin by liquid chromatography-mass spectrometry showed that the proportion of isomers at all three sites increased in order of aggregation level (α-crystallin < HMW < WI fractions). Among the abnormal isomers of Asp58 and Asp151, Dβ-isomers were predominant with a very few exceptions. Notably, the chaperone activity of HMW protein was minimal for lens of all ages, whereas that of α-crystallin decreased with increasing lens age. Thus, abnormal aggregation caused by Asp isomerization might contribute to the loss of chaperone activity of α-crystallin in aged human lens.
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Affiliation(s)
- Noriko Fujii
- Institute for Integrated Radiation and Nuclear Science, Kyoto University Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan.
| | - Takumi Takata
- Institute for Integrated Radiation and Nuclear Science, Kyoto University Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan
| | - Ingu Kim
- Institute for Integrated Radiation and Nuclear Science, Kyoto University Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan
| | - Ken Morishima
- Institute for Integrated Radiation and Nuclear Science, Kyoto University Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan
| | - Rintaro Inoue
- Institute for Integrated Radiation and Nuclear Science, Kyoto University Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan
| | - Kousuke Magami
- Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | | | - Masaaki Sugiyama
- Institute for Integrated Radiation and Nuclear Science, Kyoto University Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan
| | - Tamaki Koide
- Rexxam Co., Ltd., Nishi-ku, Nagoya, Aichi 541-0054, Japan
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23
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Brodbelt JS, Morrison LJ, Santos I. Ultraviolet Photodissociation Mass Spectrometry for Analysis of Biological Molecules. Chem Rev 2020; 120:3328-3380. [PMID: 31851501 PMCID: PMC7145764 DOI: 10.1021/acs.chemrev.9b00440] [Citation(s) in RCA: 139] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The development of new ion-activation/dissociation methods continues to be one of the most active areas of mass spectrometry owing to the broad applications of tandem mass spectrometry in the identification and structural characterization of molecules. This Review will showcase the impact of ultraviolet photodissociation (UVPD) as a frontier strategy for generating informative fragmentation patterns of ions, especially for biological molecules whose complicated structures, subtle modifications, and large sizes often impede molecular characterization. UVPD energizes ions via absorption of high-energy photons, which allows access to new dissociation pathways relative to more conventional ion-activation methods. Applications of UVPD for the analysis of peptides, proteins, lipids, and other classes of biologically relevant molecules are emphasized in this Review.
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Affiliation(s)
- Jennifer S. Brodbelt
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Lindsay J. Morrison
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
| | - Inês Santos
- Department of Chemistry, University of Texas at Austin, Austin, Texas 78712, United States
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24
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Li G, Delafield DG, Li L. Improved structural elucidation of peptide isomers and their receptors using advanced ion mobility-mass spectrometry. Trends Analyt Chem 2020. [DOI: 10.1016/j.trac.2019.05.048] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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25
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Ivanov DG, Indeykina MI, Pekov SI, Bugrova AE, Kechko OI, Iusupov AE, Kononikhin AS, Makarov AA, Nikolaev EN, Popov IA. Relative Quantitation of Beta-Amyloid Peptide Isomers with Simultaneous Isomerization of Multiple Aspartic Acid Residues by Matrix Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:164-168. [PMID: 32881518 DOI: 10.1021/jasms.9b00025] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Matrix assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry can be used for rapid quantitation of peptides with various post-translational modifications (PTM), even if they do not shift the mass of the native peptide. Previously, it was shown that MALDI-TOF MS can be used for quantitation of isoD7 beta-amyloid 1-42 peptide. On the basis of the differences in the collision-induced dissociation fragmentation pattern of native Aβ, isoD7 Aβ, isoD23 Aβ, and isoD7_23 peptide (a di-isomerized peptide with both isomerization of D7 and D23 residues), we developed a MALDI-TOF-based method for simultaneous quantitation of all of these isoforms. Using multivariate regression for analysis of fragment MS data, the method allows the determination of the molar fractions of all of these isoforms with up to 16% error for mixtures with 2 pmol total amount of the beta-amyloid peptide.
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Affiliation(s)
- Daniil G Ivanov
- Emanuel Institute of Biochemical Physics Russian Academy of Sciences, Kosygina Street 4, 119334 Moscow, Russia
- Moscow Institute of Physics and Technology, Institutskiy pr. 9, 141700 Dolgoprudny, Moscow Region, Russia
| | - Maria I Indeykina
- Emanuel Institute of Biochemical Physics Russian Academy of Sciences, Kosygina Street 4, 119334 Moscow, Russia
- Moscow Institute of Physics and Technology, Institutskiy pr. 9, 141700 Dolgoprudny, Moscow Region, Russia
| | - Stanislav I Pekov
- Moscow Institute of Physics and Technology, Institutskiy pr. 9, 141700 Dolgoprudny, Moscow Region, Russia
- V. L. Talrose Institute for Energy Problems of Chemical Physics, N. N. Semenov Federal Center of Chemical Physics, Russian Academy of Sciences, Moscow, Russia
| | - Anna E Bugrova
- Emanuel Institute of Biochemical Physics Russian Academy of Sciences, Kosygina Street 4, 119334 Moscow, Russia
- V. I. Kulakov Research Center for Obstetrics, Gynecology and Perinatology, Ministry of Healthcare of the Russian Federation, Akademika Oparina ul. 4, 117198 Moscow, Russia
| | - Olga I Kechko
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilova ul. 32, 119991 Moscow, Russia
| | - Adel E Iusupov
- Emanuel Institute of Biochemical Physics Russian Academy of Sciences, Kosygina Street 4, 119334 Moscow, Russia
- Moscow Institute of Physics and Technology, Institutskiy pr. 9, 141700 Dolgoprudny, Moscow Region, Russia
| | - Alexey S Kononikhin
- Moscow Institute of Physics and Technology, Institutskiy pr. 9, 141700 Dolgoprudny, Moscow Region, Russia
- Skolkovo Institute of Science and Technology, Novaya Street 100, 143025 Skolkovo, Moscow Region, Russia
| | - Alexander A Makarov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilova ul. 32, 119991 Moscow, Russia
| | - Eugene N Nikolaev
- Skolkovo Institute of Science and Technology, Novaya Street 100, 143025 Skolkovo, Moscow Region, Russia
| | - Igor A Popov
- Moscow Institute of Physics and Technology, Institutskiy pr. 9, 141700 Dolgoprudny, Moscow Region, Russia
- V. L. Talrose Institute for Energy Problems of Chemical Physics, N. N. Semenov Federal Center of Chemical Physics, Russian Academy of Sciences, Moscow, Russia
- V. I. Kulakov Research Center for Obstetrics, Gynecology and Perinatology, Ministry of Healthcare of the Russian Federation, Akademika Oparina ul. 4, 117198 Moscow, Russia
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26
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Probabilistic model applied to ion abundances in product-ion spectra: quantitative analysis of aspartic acid isomerization in peptides. Anal Bioanal Chem 2019; 411:7783-7789. [DOI: 10.1007/s00216-019-02174-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 09/05/2019] [Accepted: 09/25/2019] [Indexed: 12/29/2022]
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27
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Molecular basis for chirality-regulated Aβ self-assembly and receptor recognition revealed by ion mobility-mass spectrometry. Nat Commun 2019; 10:5038. [PMID: 31695027 PMCID: PMC6834639 DOI: 10.1038/s41467-019-12346-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Accepted: 09/02/2019] [Indexed: 12/22/2022] Open
Abstract
Despite extensive efforts on probing the mechanism of Alzheimer’s disease (AD) and enormous investments into AD drug development, the lack of effective disease-modifying therapeutics and the complexity of the AD pathogenesis process suggest a great need for further insights into alternative AD drug targets. Herein, we focus on the chiral effects of truncated amyloid beta (Aβ) and offer further structural and molecular evidence for epitope region-specific, chirality-regulated Aβ fragment self-assembly and its potential impact on receptor-recognition. A multidimensional ion mobility-mass spectrometry (IM-MS) analytical platform and in-solution kinetics analysis reveal the comprehensive structural and molecular basis for differential Aβ fragment chiral chemistry, including the differential and cooperative roles of chiral Aβ N-terminal and C-terminal fragments in receptor recognition. Our method is applicable to many other systems and the results may shed light on the potential development of novel AD therapeutic strategies based on targeting the D-isomerized Aβ, rather than natural L-Aβ. Chiral inversion of amino acids is thought to modulate the structure and function of amyloid beta (Aβ) but these processes are poorly understood. Here, the authors develop an ion mobility-mass spectrometry based approach to study chirality-regulated structural features of Aβ fragments and their influence on receptor recognition.
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28
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Shi Y, Zhou M, Zhang K, Ma L, Kong X. Chiral Differentiation of Non-Covalent Diastereomers Based on Multichannel Dissociation Induced by 213-nm Ultraviolet Photodissociation. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2019; 30:2297-2305. [PMID: 31410655 DOI: 10.1007/s13361-019-02302-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 07/10/2019] [Accepted: 07/23/2019] [Indexed: 06/10/2023]
Abstract
Here we present the implementation of 213-nm ultraviolet photodissociation (UVPD) in a FT-ICR mass spectrometer for chiral differentiation in the gas phase. The L/D amino acid-substituted serine octamer ions were selected as examples of diastereoisomers for chiral analysis. Several kinds of fragment ions were observed in these experiments, including fragment ions that are similar to the ones observed in corresponding collision-activated dissociation (CAD) experiments, fragment ions generated with different protonation sites by only destroying non-covalent bonds, and unique non-covalent cluster radical ions. The latter two kinds of fragment ions are found to be more sensitive to the chirality of the substituted units. Further experiments suggest that the formation of radical ions is mainly affected by chromophores on side chains of the substituted units and micro surroundings of the characterized non-covalent diastereoisomers. A comparing experiment performed by only changing the wavelength of UV laser to 266 nm shows that the 213-nm UV laser has the priority in the diversity of fragmentation pathways and potential of further application in chiral differentiation experiments.
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Affiliation(s)
- Yingying Shi
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Nankai University, Tianjin, 300071, China
| | - Min Zhou
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Nankai University, Tianjin, 300071, China
- Department of Physics, Anhui Normal University, Wuhu, 241000, People's Republic of China
| | - Kailin Zhang
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Nankai University, Tianjin, 300071, China
- School of Precision Instrument and Opto-Electronics Engineering, Tianjin University, Tianjin, 300072, China
| | - Lifu Ma
- School of Precision Instrument and Opto-Electronics Engineering, Tianjin University, Tianjin, 300072, China
| | - Xianglei Kong
- State Key Laboratory and Institute of Elemento-Organic Chemistry, Nankai University, Tianjin, 300071, China.
- Collaborative Innovation Center of Chemical Science and Engineering, Nankai University, Tianjin, 300071, China.
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Riggs DL, Silzel JW, Lyon YA, Kang AS, Julian RR. Analysis of Glutamine Deamidation: Products, Pathways, and Kinetics. Anal Chem 2019; 91:13032-13038. [PMID: 31498611 PMCID: PMC8805438 DOI: 10.1021/acs.analchem.9b03127] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Spontaneous chemical modifications play an important role in human disease and aging at the molecular level. Deamidation and isomerization are known to be among the most prevalent chemical modifications in long-lived human proteins and are implicated in a growing list of human pathologies, but the relatively minor chemical change associated with these processes has presented a long standing analytical challenge. Although the adoption of high-resolution mass spectrometry has greatly aided the identification of deamidation sites in proteomic studies, isomerization (and the isomeric products of deamidation) remain exceptionally challenging to characterize. Herein, we present a liquid chromatography/mass spectrometry-based approach for rapidly characterizing the isomeric products of Gln deamidation using diagnostic fragments that are abundantly produced and capable of unambiguously identifying both Glu and isoGlu. Importantly, the informative fragment ions are produced through orthogonal fragmentation pathways, thereby enabling the simultaneous detection of both isomeric forms while retaining compatibility with shotgun proteomics. Furthermore, the diagnostic fragments associated with isoGlu pinpoint the location of the modified residue. The utility of this technique is demonstrated by characterizing the isomeric products generated during in vitro aging of a series of glutamine-containing peptides. Sequence-dependent product profiles are obtained, and the abundance of deamidation-linked racemization is examined. Finally, comparisons are made between Gln deamidation, which is relatively poorly understood, and asparagine deamidation, which has been more thoroughly studied.
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Affiliation(s)
- Dylan L. Riggs
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Jacob W. Silzel
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Yana A. Lyon
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Amrik S. Kang
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Ryan R. Julian
- Department of Chemistry, University of California, Riverside, California 92521, United States
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30
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Buchowiecka AK. Modified cysteine S-phosphopeptide standards for mass spectrometry-based proteomics. Amino Acids 2019; 51:1365-1375. [DOI: 10.1007/s00726-019-02773-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 08/18/2019] [Indexed: 02/06/2023]
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31
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Foley AR, Finn TS, Kung T, Hatami A, Lee HW, Jia M, Rolandi M, Raskatov JA. Trapping and Characterization of Nontoxic Aβ42 Aggregation Intermediates. ACS Chem Neurosci 2019; 10:3880-3887. [PMID: 31319029 DOI: 10.1021/acschemneuro.9b00340] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Amyloid β (Aβ) 42 is an aggregation-prone peptide and the believed seminal etiological agent of Alzheimer's disease (AD). Intermediates of Aβ42 aggregation, commonly referred to as diffusible oligomers, are considered to be among the most toxic forms of the peptide. Here, we studied the effect of the age-related epimerization of Ser26 (i.e., S26s chiral edit) in Aβ42 and discovered that this subtle molecular change led to reduced fibril formation propensity. Surprisingly, the resultant soluble aggregates were nontoxic. To gain insight into the structural changes that occurred in the peptide upon S26s substitution, the system was probed using an array of biophysical and biochemical methods. These experiments consistently pointed to the stabilization of aggregation intermediates in the Aβ42-S26s system. To better understand the changes arising as a consequence of the S26s substitution, molecular level structural studies were performed. Using a combined nuclear magnetic resonance (NMR)- and density functional theory (DFT)-computational approach, we found that the S26s chiral edit induced only local structural changes in the Gly25-Ser26-Asn27 region. Interestingly, these subtle changes enabled the formation of an intramolecular Ser26-Asn27 H-bond, which disrupted the ability of Asn27 to engage in the fibrillogenic side chain-to-side chain H-bonding pattern. This reveals that intermolecular stabilizing interactions between Asn27 side chains are a key element controlling Aβ42 aggregation and toxicity.
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Affiliation(s)
- Alejandro R. Foley
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California 95064, United States
| | - Thomas S. Finn
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California 95064, United States
| | - Timothy Kung
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California 95064, United States
| | - Asa Hatami
- Sangamo Therapeutics, Richmond, California 94804, United States
| | - Hsiau-Wei Lee
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California 95064, United States
| | - Manping Jia
- Department of Electrical Engineering, University of California Santa Cruz, Santa Cruz, California 95064, United States
| | - Marco Rolandi
- Department of Electrical Engineering, University of California Santa Cruz, Santa Cruz, California 95064, United States
| | - Jevgenij A. Raskatov
- Department of Chemistry and Biochemistry, University of California Santa Cruz, Santa Cruz, California 95064, United States
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Lyon YA, Collier MP, Riggs DL, Degiacomi MT, Benesch JLP, Julian RR. Structural and functional consequences of age-related isomerization in α-crystallins. J Biol Chem 2019; 294:7546-7555. [PMID: 30804217 PMCID: PMC6514633 DOI: 10.1074/jbc.ra118.007052] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 02/15/2019] [Indexed: 12/31/2022] Open
Abstract
Long-lived proteins are subject to spontaneous degradation and may accumulate a range of modifications over time, including subtle alterations such as side-chain isomerization. Recently, tandem MS has enabled identification and characterization of such peptide isomers, including those differing only in chirality. However, the structural and functional consequences of these perturbations remain largely unexplored. Here, we examined the impact of isomerization of aspartic acid or epimerization of serine at four sites mapping to crucial oligomeric interfaces in human αA- and αB-crystallin, the most abundant chaperone proteins in the eye lens. To characterize the effect of isomerization on quaternary assembly, we utilized synthetic peptide mimics, enzyme assays, molecular dynamics calculations, and native MS experiments. The oligomerization of recombinant forms of αA- and αB-crystallin that mimic isomerized residues deviated from native behavior in all cases. Isomerization also perturbs recognition of peptide substrates, either enhancing or inhibiting kinase activity. Specifically, epimerization of serine (αASer-162) dramatically weakened inter-subunit binding. Furthermore, phosphorylation of αBSer-59, known to play an important regulatory role in oligomerization, was severely inhibited by serine epimerization and altered by isomerization of nearby αBAsp-62. Similarly, isomerization of αBAsp-109 disrupted a vital salt bridge with αBArg-120, a contact that when broken has previously been shown to yield aberrant oligomerization and aggregation in several disease-associated variants. Our results illustrate how isomerization of amino acid residues, which may seem to be only a minor structural perturbation, can disrupt native structural interactions with profound consequences for protein assembly and activity.
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Affiliation(s)
- Yana A Lyon
- From the Department of Chemistry, University of California, Riverside, Riverside, California 92521
| | - Miranda P Collier
- the Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom, and
| | - Dylan L Riggs
- From the Department of Chemistry, University of California, Riverside, Riverside, California 92521
| | - Matteo T Degiacomi
- the Department of Chemistry, Durham University, South Road, Durham DH1 3LE, United Kingdom
| | - Justin L P Benesch
- the Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, United Kingdom, and
| | - Ryan R Julian
- From the Department of Chemistry, University of California, Riverside, Riverside, California 92521,
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Differentiation of peptide isomers and epimers by radical-directed dissociation. Methods Enzymol 2019; 626:67-87. [DOI: 10.1016/bs.mie.2019.06.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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34
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Identification of D-Amino Acids in Light Exposed mAb Formulations. Pharm Res 2018; 35:238. [PMID: 30334107 DOI: 10.1007/s11095-018-2520-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 10/05/2018] [Indexed: 12/14/2022]
Abstract
PURPOSE We previously demonstrated that D-amino acids can form as a result of photo-irradiation of a monoclonal antibody (mAb) at both λ = 254 nm and λ > 295 nm (λmax = 305 nm), likely via reversible hydrogen transfer reactions of intermediary thiyl radicals. Here, we investigate the role of various excipients (sucrose, glucose, L-Arg, L-Met and L-Leu) on D-amino acid formation, and specifically the distribution of D-amino acids in mAb monomers and aggregates present after light exposure. METHODS The mAb-containing formulations were photo-irradiated at λ = 254 nm and λmax = 305 nm, followed by fractionation of aggregate and monomer fractions using size exclusion chromatography. These aggregate and monomer fractions were subjected to hydrolysis and subsequent amino acid analysis. RESULTS Both aggregate and monomer fractions collected from all formulations showed the formation of D-Glu and D-Val, whereas the formation of D-Ala was limited to the aggregate fraction collected from an L-Arg-containing formulation. Interestingly, quantitative analysis revealed higher yields of D-amino acids in the L-Arg-containing formulation. CONCLUSIONS Generally, D-amino acids accumulated to similar extents in monomers and aggregates.
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Checco JW, Zhang G, Yuan WD, Le ZW, Jing J, Sweedler JV. Aplysia allatotropin-related peptide and its newly identified d-amino acid-containing epimer both activate a receptor and a neuronal target. J Biol Chem 2018; 293:16862-16873. [PMID: 30194283 DOI: 10.1074/jbc.ra118.004367] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 09/04/2018] [Indexed: 12/13/2022] Open
Abstract
l- to d-residue isomerization is a post-translational modification (PTM) present in neuropeptides, peptide hormones, and peptide toxins from several animals. In most cases, the d-residue is critical for the biological function of the resulting d-amino acid-containing peptide (DAACP). Here, we provide an example in native neuropeptides in which the DAACP and its all-l-amino acid epimer are both active at their newly identified receptor in vitro and at a neuronal target associated with feeding behavior. On the basis of sequence similarity to a known DAACP from cone snail venom, we hypothesized that allatotropin-related peptide (ATRP), a neuropeptide from the neuroscience model organism Aplysia californica, may form multiple diastereomers in the Aplysia central nervous system. We determined that ATRP exists as a d-amino acid-containing peptide (d2-ATRP) and identified a specific G protein-coupled receptor as an ATRP receptor. Interestingly, unlike many previously reported DAACPs and their all-l-residue analogs, both l-ATRP and d2-ATRP were potent agonists of this receptor and active in electrophysiological experiments. Finally, d2-ATRP was much more stable than its all-l-residue counterpart in Aplysia plasma, suggesting that in the case of ATRP, the primary role of the l- to d-residue isomerization may be to protect this peptide from aminopeptidase activity in the extracellular space. Our results indicate that l- to d-residue isomerization can occur even in an all-l-residue peptide with a known biological activity and that in some cases, this PTM may help modulate peptide signal lifetime in the extracellular space rather than activity at the cognate receptor.
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Affiliation(s)
- James W Checco
- From the Beckman Institute for Advanced Science and Technology and
| | - Guo Zhang
- the State Key Laboratory of Pharmaceutical Biotechnology, Institute for Brain Sciences, Collaborative Innovation Center of Chemistry for Life Sciences, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Advanced Institute for Life Sciences, School of Life Sciences, Nanjing University, Jiangsu 210046, China
| | - Wang-Ding Yuan
- the State Key Laboratory of Pharmaceutical Biotechnology, Institute for Brain Sciences, Collaborative Innovation Center of Chemistry for Life Sciences, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Advanced Institute for Life Sciences, School of Life Sciences, Nanjing University, Jiangsu 210046, China
| | - Zi-Wei Le
- the State Key Laboratory of Pharmaceutical Biotechnology, Institute for Brain Sciences, Collaborative Innovation Center of Chemistry for Life Sciences, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Advanced Institute for Life Sciences, School of Life Sciences, Nanjing University, Jiangsu 210046, China
| | - Jian Jing
- the State Key Laboratory of Pharmaceutical Biotechnology, Institute for Brain Sciences, Collaborative Innovation Center of Chemistry for Life Sciences, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Advanced Institute for Life Sciences, School of Life Sciences, Nanjing University, Jiangsu 210046, China
| | - Jonathan V Sweedler
- From the Beckman Institute for Advanced Science and Technology and .,the Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 and
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Fujii N, Takata T, Fujii N, Aki K, Sakaue H. D-Amino acids in protein: The mirror of life as a molecular index of aging. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018. [DOI: 10.1016/j.bbapap.2018.03.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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37
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Checco JW, Zhang G, Yuan WD, Yu K, Yin SY, Roberts-Galbraith RH, Yau PM, Romanova EV, Jing J, Sweedler JV. Molecular and Physiological Characterization of a Receptor for d-Amino Acid-Containing Neuropeptides. ACS Chem Biol 2018. [PMID: 29543428 PMCID: PMC5962930 DOI: 10.1021/acschembio.8b00167] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
![]()
Neuropeptides
in several animals undergo an unusual post-translational
modification, the isomerization of an amino acid residue from the l-stereoisomer to the d-stereoisomer. The resulting d-amino acid-containing peptide (DAACP) often displays biological
activity higher than that of its all-l-residue analogue,
with the d-residue being critical for function in many cases.
However, little is known about the full physiological roles played
by DAACPs, and few studies have examined the interaction of DAACPs
with their cognate receptors. Here, we characterized the signaling
of several DAACPs derived from a single neuropeptide prohormone, the Aplysia californica achatin-like neuropeptide precursor
(apALNP), at their putative receptor, the achatin-like neuropeptide
receptor (apALNR). We first used quantitative polymerase chain reaction
and in situ hybridization experiments to demonstrate
receptor (apALNR) expression throughout the central
nervous system; on the basis of the expression pattern, we identified
novel physiological functions that may be mediated by apALNR. To gain
insight into ligand signaling through apALNR, we created a library
of native and non-native neuropeptide analogues derived from apALNP
(the neuropeptide prohormone) and evaluated them for activity in cells
co-transfected with apALNR and the promiscuous Gα
subunit Gα-16. Several of these neuropeptide
analogues were also evaluated for their ability to induce circuit
activity in a well-defined neural network associated with feeding
behavior in intact ganglia from Aplysia. Our results
reveal the specificity of apALNR and provide strong evidence that
this receptor mediates diverse physiological functions throughout
the central nervous system. Finally, we show that some native apALNP-derived
DAACPs exhibit enhanced stability toward endogenous proteases, suggesting
that the d-residues in these DAACPs may increase the peptide
lifetime, in addition to influencing receptor specificity, in the
nervous system. Ultimately, these studies provide insight into signaling
at one of the few known DAACP-specific receptors and advance our understanding
of the roles that l- to d-residue isomerization
play in neuropeptide signaling.
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Affiliation(s)
- James W. Checco
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Guo Zhang
- State Key Laboratory of Pharmaceutical Biotechnology, Collaborative Innovation Center of Chemistry for Life Sciences, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Advanced Institute for Life Sciences, School of Life Sciences, Nanjing University, Nanjing, China
| | - Wang-ding Yuan
- State Key Laboratory of Pharmaceutical Biotechnology, Collaborative Innovation Center of Chemistry for Life Sciences, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Advanced Institute for Life Sciences, School of Life Sciences, Nanjing University, Nanjing, China
| | - Ke Yu
- State Key Laboratory of Pharmaceutical Biotechnology, Collaborative Innovation Center of Chemistry for Life Sciences, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Advanced Institute for Life Sciences, School of Life Sciences, Nanjing University, Nanjing, China
| | - Si-yuan Yin
- State Key Laboratory of Pharmaceutical Biotechnology, Collaborative Innovation Center of Chemistry for Life Sciences, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Advanced Institute for Life Sciences, School of Life Sciences, Nanjing University, Nanjing, China
| | - Rachel H. Roberts-Galbraith
- Department of Cell and Developmental Biology, Howard Hughes Medical Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Peter M. Yau
- Roy J. Carver Biotechnology Center, Protein Sciences Facility, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Elena V. Romanova
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Jian Jing
- State Key Laboratory of Pharmaceutical Biotechnology, Collaborative Innovation Center of Chemistry for Life Sciences, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Advanced Institute for Life Sciences, School of Life Sciences, Nanjing University, Nanjing, China
| | - Jonathan V. Sweedler
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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Lyon YA, Sabbah GM, Julian RR. Differences in α-Crystallin isomerization reveal the activity of protein isoaspartyl methyltransferase (PIMT) in the nucleus and cortex of human lenses. Exp Eye Res 2018; 171:131-141. [PMID: 29571628 DOI: 10.1016/j.exer.2018.03.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 02/16/2018] [Accepted: 03/19/2018] [Indexed: 01/12/2023]
Abstract
Although it is well-known that protein turnover essentially stops in mature lens fiber cells, mapping out the ensuing protein degradation and its effects on lens function over time remains challenging. In particular, isomerization is a common, spontaneous post-translational modification that occurs over long timescales and generates products invisible to most analytical methods. Nevertheless, isomerization can significantly impact protein structure, function, and solubility, which are all necessary to maintain clarity and proper refractive index within the lens. Herein, we examine the degree of isomerization occurring in crystallin proteins in the human eye lens as a function of both age and location within the lens. A novel mass spectrometric technique leveraging radical chemistry enables detailed characterization of proteins extracted from the cortex and nucleus of the lens. It is observed that the degree of isomerization increases significantly between the cortex and nucleus and between water-soluble and water-insoluble fractions. Interestingly, the abundance of L-isoAsp is low in the water-soluble cortex despite being the dominant product generated by isomerization of Asp in vitro, suggesting that Protein L-isoaspartyl methyltransferase (PIMT) is active in the cortex and suppresses the accumulation of L-isoAsp. The abundance of L-isoAsp increases dramatically in the nucleus, revealing that PIMT activity decreases over time in the center of the lens. In addition, the growth of L-isoAsp in the nuclear fraction suggests protein isomerization continues within the nucleus, despite the fact that most of the protein within the nucleus has become insoluble. Additionally, it is demonstrated that sequential Asp residues lead to isomerization hotspots in human crystallin proteins and that the isomerization profiles for αA and αB crystallin are notably different. Although αA is more prone to isomerization, αB loses solubility more rapidly upon modification. These differences are likely related to the distribution of Asp residues within αA and αB, which are in turn connected to refractive index. The high Asp content of αA is a hazard in terms of isomerization and aging, but it serves to enhance the refractive index of αA relative to αB, and may explain why αA is only found in the eye.
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Affiliation(s)
- Yana A Lyon
- Department of Chemistry, University of California, Riverside, 501 Big Springs Road, Riverside, CA 92521, USA
| | - Georgette M Sabbah
- Department of Chemistry, University of California, Riverside, 501 Big Springs Road, Riverside, CA 92521, USA
| | - Ryan R Julian
- Department of Chemistry, University of California, Riverside, 501 Big Springs Road, Riverside, CA 92521, USA.
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Miyamoto T, Homma H. Detection and quantification of d-amino acid residues in peptides and proteins using acid hydrolysis. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1866:775-782. [PMID: 29292238 DOI: 10.1016/j.bbapap.2017.12.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 12/04/2017] [Accepted: 12/19/2017] [Indexed: 12/14/2022]
Abstract
Biomolecular homochirality refers to the assumption that amino acids in all living organisms were believed to be of the l-configuration. However, free d-amino acids are present in a wide variety of organisms and d-amino acid residues are also found in various peptides and proteins, being generated by enzymatic or non-enzymatic isomerization. In mammals, peptides and proteins containing d-amino acids have been linked to various diseases, and they act as novel disease biomarkers. Analytical methods capable of precisely detecting and quantifying d-amino acids in peptides and proteins are therefore important and useful, albeit their difficulty and complexity. Herein, we reviewed conventional analytical methods, especially 0h extrapolating method, and the problems of this method. For the solution of these problems, we furthermore described our recently developed, sensitive method, deuterium-hydrogen exchange method, to detect innate d-amino acid residues in peptides and proteins, and its applications to sample ovalbumin. This article is part of a Special Issue entitled: d-Amino acids: biology in the mirror, edited by Dr. Loredano Pollegioni, Dr. Jean-Pierre Mothet and Dr. Molla Gianluca.
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Affiliation(s)
- Tetsuya Miyamoto
- Graduate School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan
| | - Hiroshi Homma
- Graduate School of Pharmaceutical Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan.
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40
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Racemization of Serine Residues Catalyzed by Dihydrogen Phosphate Ion: A Computational Study. Catalysts 2017. [DOI: 10.3390/catal7120363] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Spontaneous, nonenzymatic reactions in proteins are known to have relevance to aging and age-related diseases, such as cataract and Alzheimer’s disease. Among such reactions is the racemization of Ser residues, but its mechanism in vivo remains to be clarified. The most likely intermediate is an enol. Although being nonenzymatic, the enolization would need to be catalyzed to occur at a biologically relevant rate. In the present study, we computationally found plausible reaction pathways for the enolization of a Ser residue where a dihydrogen phosphate ion, H2PO4−, acts as a catalyst. The H2PO4− ion mediates the proton transfer required for the enolization by acting simultaneously as both a general base and a general acid. Using the B3LYP density functional theory method, reaction pathways were located in the gas phase and hydration effects were evaluated by single-point calculations using the SM8 continuum model. The activation barriers calculated for the reaction pathways found were around 100 kJ mol−1, which is consistent with spontaneous reactions occurring at physiological temperature. Our results are also consistent with experimental observations that Ser residue racemization occurs more readily in flexible regions in proteins.
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41
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Riggs DL, Gomez SV, Julian RR. Sequence and Solution Effects on the Prevalence of d-Isomers Produced by Deamidation. ACS Chem Biol 2017; 12:2875-2882. [PMID: 28984444 PMCID: PMC5696650 DOI: 10.1021/acschembio.7b00686] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Deamidation of asparagine is a spontaneous and irreversible post-translational modification associated with a growing list of human diseases. While pervasive, deamidation is often overlooked because it represents a relatively minor chemical change. Structural and functional characterization of this modification is complicated because deamidation of asparagine yields four isomeric forms of Asp. Herein, radical directed dissociation (RDD), in conjunction with mass spectrometry, is used to identify and quantify all four isomers in a series of model peptides that were subjected to various deamidation conditions. Although primary sequence significantly influences the rate of deamidation, it has little impact on the relative proportions of the product isomers. Furthermore, the addition of ammonia can be used to increase the rate of deamidation without significantly perturbing isomer populations. Conversely, external factors such as buffer conditions and temperature alter product distributions but exhibit less dramatic effects on the deamidation rate. Strikingly, the common laboratory and biologically significant bicarbonate buffer is found to strongly promote racemization, yielding increased amounts of d-Asp and d-isoAsp. These outcomes following deamidation have broad implications in human aging and should be considered during the development of protein-based therapeutics.
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Affiliation(s)
- Dylan L. Riggs
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Sonia V. Gomez
- Department of Chemistry, University of California, Riverside, California 92521, United States
| | - Ryan R. Julian
- Department of Chemistry, University of California, Riverside, California 92521, United States
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42
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Jansson ET. Strategies for analysis of isomeric peptides. J Sep Sci 2017; 41:385-397. [PMID: 28922569 DOI: 10.1002/jssc.201700852] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Revised: 09/06/2017] [Accepted: 09/06/2017] [Indexed: 01/09/2023]
Abstract
This review presents an overview and recent progress of strategies for detecting isomerism in peptides, with focus on d/l epimerization and the various isomers that the presence of an aspartic acid residue may yield in a protein or peptide. While mass spectrometry has become a majorly used method of choice within proteomics, isomerism is inherently difficult to analyze because it is a modification that does not yield any change in mass of the analyte. Here, several techniques used for analysis of peptide isomerism are discussed, including enzymatic assays, liquid chromatography, and capillary electrophoresis. Recent progress in method development using mass spectrometry is also discussed, including labeling strategies, fragmentation techniques, and ion-mobility spectrometry.
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Affiliation(s)
- Erik T Jansson
- Department of Chemistry-BMC, Uppsala University, Uppsala, Sweden
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43
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Zheng X, Deng L, Baker ES, Ibrahim YM, Petyuk VA, Smith RD. Distinguishing d- and l-aspartic and isoaspartic acids in amyloid β peptides with ultrahigh resolution ion mobility spectrometry. Chem Commun (Camb) 2017; 53:7913-7916. [PMID: 28654112 PMCID: PMC5555368 DOI: 10.1039/c7cc03321d] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
While α-linked amino acids in the l-form are exclusively utilized in mammalian protein building, β-linked and d-form amino acids also have important biological roles. Unfortunately, the structural elucidation and separation of these different amino acid types in peptides has been analytically challenging to date due to the numerous isomers present, limiting our knowledge about their existence and biological roles. Here, we utilized an ultrahigh resolution ion mobility spectrometry platform coupled with mass spectrometry (IMS-MS) to separate amyloid β (Aβ) peptides containing l-aspartic acid, d-aspartic acid, l-isoaspartic acid, and d-isoaspartic acid residues which span α- and β-linked amino acids in both d- and l-forms. The results illustrate how IMS-MS could be used to better understand age-related diseases or protein folding disorders resulting from amino acid modifications.
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Affiliation(s)
- Xueyun Zheng
- Biological Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA 99352 USA
| | - Liulin Deng
- Biological Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA 99352 USA
| | - Erin S. Baker
- Biological Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA 99352 USA
| | - Yehia M. Ibrahim
- Biological Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA 99352 USA
| | - Vladislav A. Petyuk
- Biological Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA 99352 USA
| | - Richard D. Smith
- Biological Sciences Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA 99352 USA
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44
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Lyon YA, Beran G, Julian RR. Leveraging Electron Transfer Dissociation for Site Selective Radical Generation: Applications for Peptide Epimer Analysis. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:1365-1373. [PMID: 28374314 PMCID: PMC5497491 DOI: 10.1007/s13361-017-1627-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2016] [Revised: 02/07/2017] [Accepted: 02/08/2017] [Indexed: 06/07/2023]
Abstract
Traditional electron-transfer dissociation (ETD) experiments operate through a complex combination of hydrogen abundant and hydrogen deficient fragmentation pathways, yielding c and z ions, side-chain losses, and disulfide bond scission. Herein, a novel dissociation pathway is reported, yielding homolytic cleavage of carbon-iodine bonds via electronic excitation. This observation is very similar to photodissociation experiments where homolytic cleavage of carbon-iodine bonds has been utilized previously, but ETD activation can be performed without addition of a laser to the mass spectrometer. Both loss of iodine and loss of hydrogen iodide are observed, with the abundance of the latter product being greatly enhanced for some peptides after additional collisional activation. These observations suggest a novel ETD fragmentation pathway involving temporary storage of the electron in a charge-reduced arginine side chain. Subsequent collisional activation of the peptide radical produced by loss of HI yields spectra dominated by radical-directed dissociation, which can be usefully employed for identification of peptide isomers, including epimers. Graphical Abstract ᅟ.
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Affiliation(s)
- Yana A Lyon
- Department of Chemistry, University of California-Riverside, 501 Big Springs Road, Riverside, CA, 92521, USA
| | - Gregory Beran
- Department of Chemistry, University of California-Riverside, 501 Big Springs Road, Riverside, CA, 92521, USA
| | - Ryan R Julian
- Department of Chemistry, University of California-Riverside, 501 Big Springs Road, Riverside, CA, 92521, USA.
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45
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de Castro P, Rimulo IMR, de Almeida AM, Diniz R, Amarante GW. Brønsted Acid-Catalyzed Epimerization-Free Preparation of Dual-Protected Amino Acid Derivatives. ACS OMEGA 2017; 2:2967-2976. [PMID: 31457632 PMCID: PMC6641006 DOI: 10.1021/acsomega.7b00523] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 06/14/2017] [Indexed: 06/10/2023]
Abstract
An organocatalytic protocol, employing the commercially available EDC as coupling agent, has been developed for the preparation of dual-protected amino acid derivatives without epimerization. This methodology was then applied to different Boc-amino acid and amine derivatives in moderate to excellent isolated yields. In addition, racemization-free Boc deprotection was also demonstrated. Mechanism investigation through electrospray ionization (+)-mass spectrometry/mass spectrometry revealed an acyclic intermediate (no azlactone formation) activated by the camphorsulfonic acid as an organocatalyst as a key step for the sequential attack of the nucleophile.
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Affiliation(s)
- Pedro
P. de Castro
- Department
of Chemistry, Federal University of Juiz
de Fora, Campus Martelos, Juiz de Fora, Minas Gerais 36036-900, Brazil
| | - Isabela M. R. Rimulo
- Department
of Chemistry, Federal University of Juiz
de Fora, Campus Martelos, Juiz de Fora, Minas Gerais 36036-900, Brazil
| | - Angelina M. de Almeida
- Department
of Chemistry, Federal University of Juiz
de Fora, Campus Martelos, Juiz de Fora, Minas Gerais 36036-900, Brazil
| | - Renata Diniz
- Department
of Chemistry, Federal University of Minas
Gerais, Campus Pampulha, Belo Horizonte, Minas Gerais 31270-901, Brazil
| | - Giovanni W. Amarante
- Department
of Chemistry, Federal University of Juiz
de Fora, Campus Martelos, Juiz de Fora, Minas Gerais 36036-900, Brazil
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46
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Lyon YA, Sabbah GM, Julian RR. Identification of Sequence Similarities among Isomerization Hotspots in Crystallin Proteins. J Proteome Res 2017; 16:1797-1805. [PMID: 28234481 PMCID: PMC5387677 DOI: 10.1021/acs.jproteome.7b00073] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
The eye lens crystallins represent
an ideal target for studying
the effects of aging on protein structure. Herein we examine separately
the water-soluble (WS) and water-insoluble (WI) crystallin fractions
and identify sites of isomerization and epimerization. Both collision-induced
dissociation and radical-directed dissociation are needed for detection
of these non-mass-shifting post-translational modifications. Isomerization
levels differ significantly between the WS and the WI fractions from
sheep, pig, and cow eye lenses. Residues that are most susceptible
to isomerization are identified site-specifically and are found to
reside in structurally disordered regions. However, isomerization
in structured domains, although less common, often yields more dramatic
effects on solubility. Numerous isomerization hotspots were also identified
and occur in regions with aspartic acid and serine repeats. For example, 128KMEIVDDDVPSLW140 in βB3
crystallin contains three sequential aspartic acid residues and is
isomerized heavily in the WI fractions, while it is not modified at
all in the WS fractions. Potential causes for enhanced isomerization
at sites with acidic residue repeats are presented. The importance
of acidic residue repeats extends beyond the lens, as they are found
in many other long-lived proteins associated with disease.
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Affiliation(s)
- Yana A Lyon
- Department of Chemistry, University of California , Riverside, 501 Big Springs Road, Riverside, California 92521, United States
| | - Georgette M Sabbah
- Department of Chemistry, University of California , Riverside, 501 Big Springs Road, Riverside, California 92521, United States
| | - Ryan R Julian
- Department of Chemistry, University of California , Riverside, 501 Big Springs Road, Riverside, California 92521, United States
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47
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Pang X, Jia C, Chen Z, Li L. Structural Characterization of Monomers and Oligomers of D-Amino Acid-Containing Peptides Using T-Wave Ion Mobility Mass Spectrometry. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2017; 28:110-118. [PMID: 27822705 PMCID: PMC5177490 DOI: 10.1007/s13361-016-1523-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 10/04/2016] [Accepted: 10/06/2016] [Indexed: 05/03/2023]
Abstract
The D-residues are crucial to biological function of D-amino acid containing peptides (DAACPs). Previous ion mobility mass spectrometry (IM-MS) studies revealing oligomerization patterns of amyloid cascade demonstrated conversion from native soluble unstructured assembly to fibril ß-sheet oligomers, which has been implicated in amyloid diseases, such as Alzheimer's disease and type 2 diabetes. Although neuropeptides are typically present at very low concentrations in circulation, their local concentrations could be much higher in large dense core vesicles, forming dimers or oligomers. We studied the oligomerization of protonated and metal-adducted achatin I and dermorphin peptide isomers with IM-MS. Our results suggested that dimerization, oligomerization, and metal adduction augment the structural differences between D/L peptide isomers compared to protonated monomers. Dimers and oligomers enhanced the structural differences between D/L peptide isomers in both aqueous and organic solvent system. Furthermore, some oligomer forms were only observed for either D- or L-isomers, indicating the importance of chiral center in oligomerization process. The oligomerization patterns of D/L isomers appear to be similar. Potassium adducts were detected to enlarge the structural differences between D/L isomers. Graphical Abstract ᅟ.
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Affiliation(s)
- Xueqin Pang
- School of Pharmacy, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Chenxi Jia
- School of Pharmacy, University of Wisconsin-Madison, Madison, WI, 53705, USA
- National Center for Protein Sciences-Beijing, Beijing Proteome Research Center, State Key Laboratory of Proteomics, Beijing Institute of Radiation Medicine, Beijing, 102206, China
| | - Zhengwei Chen
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Lingjun Li
- School of Pharmacy, University of Wisconsin-Madison, Madison, WI, 53705, USA.
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53705, USA.
- School of Life Sciences, Tianjin University, Tianjin, China.
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48
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DeGraan-Weber N, Zhang J, Reilly JP. Distinguishing Aspartic and Isoaspartic Acids in Peptides by Several Mass Spectrometric Fragmentation Methods. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2016; 27:2041-2053. [PMID: 27613306 PMCID: PMC5748252 DOI: 10.1007/s13361-016-1487-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 08/17/2016] [Accepted: 08/19/2016] [Indexed: 05/21/2023]
Abstract
Six ion fragmentation techniques that can distinguish aspartic acid from its isomer, isoaspartic acid, were compared. MALDI post-source decay (PSD), MALDI 157 nm photodissociation, tris(2,4,6-trimethoxyphenyl)phosphonium bromide (TMPP) charge tagging in PSD and photodissociation, ESI collision-induced dissociation (CID), electron transfer dissociation (ETD), and free-radical initiated peptide sequencing (FRIPS) with CID were applied to peptides containing either aspartic or isoaspartic acid. Diagnostic ions, such as the y-46 and b+H2O, are present in PSD, photodissociation, and charge tagging. c•+57 and z-57 ions are observed in ETD and FRIPS experiments. For some molecules, aspartic and isoaspartic acid yield ion fragments with significantly different intensities. ETD and charge tagging appear to be most effective at distinguishing these residues. Graphical Abstract ᅟ.
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Affiliation(s)
- Nick DeGraan-Weber
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, IN, 47405, USA
| | - Jun Zhang
- Pre-Pivotal Drug Product Technologies, Amgen Inc., Thousand Oaks, CA, 91320, USA
| | - James P Reilly
- Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, IN, 47405, USA.
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49
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Affiliation(s)
- Jennifer S Brodbelt
- Department of Chemistry, University of Texas at Austin , Austin, Texas 78712, United States
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50
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Pham HT, Julian RR. Characterization of glycosphingolipid epimers by radical-directed dissociation mass spectrometry. Analyst 2016; 141:1273-8. [DOI: 10.1039/c5an02383a] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Radical chemistry can efficiently distinguish isomers varying in position at a single alcohol.
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