CE-MS Identification of Amino Acid Sequence Inversion as a New Degradation Pathway of an Aspartyl Model Tripeptide

Brückner, Christin; Bunz, Svenja-Catharina; Neusüß, Christian; Scriba, Gerhard K. E.

doi:10.1007/s10337-012-2306-5

Cited by 3 publications

(3 citation statements)

References 21 publications

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“… 40 Furthermore, our results do not suggest a bias toward identification of isomerization for peptides that contain proline, as proline is present in both isomerized and unmodified peptides. Another type of modification that could occur in some rare cases involves two amino acids that are inverted in sequence, 41 which could lead to separation of the isomers by liquid chromatography. It is not anticipated that such isomers will occur frequently enough to significantly impact our results, and these isomers would be identified by analysis of the MS/MS data if fragmentation between the relevant residues was observed.…”

Section: Resultsmentioning

confidence: 99%

Identification of Amino Acid Epimerization and Isomerization in Crystallin Proteins by Tandem LC-MS

2014

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Post-translational modifications that do not result in a change in mass are particularly difficult to detect by mass spectrometry. For example, isomerization of aspartic acid or epimerization of any chiral residue within a peptide do not lead to mass shifts but can be identified by examination of independently acquired tandem mass spectra or by combination with another technique. For analysis of a biological sample, this means that liquid chromatography or some other type of separation must be used to first separate the isomers from one another. Furthermore, each specific m/z of interest must be sampled repeatedly to allow for comparison of the tandem mass spectra from each separated isomer, which contrasts with the traditional approach in proteomics where the goal is typically to avoid resampling the same m/z. We illustrate that isomerization and epimerization of peptides can be identified in this fashion by examination of long-lived crystallin proteins extracted from a sheep eye lens. Tandem mass spectrometry relying on a combination of radical directed dissociation (RDD) and collision induced dissociation (CID) following separation by liquid chromatography was used to identify modified peptides. Numerous sites of isomerization and epimerization, including several that have not been previously identified, were determined with peptide specificity. It is demonstrated that the specific sites of amino acid isomerization within each peptide can be identified by comparison with synthetic peptides. For α-crystallin proteins, the sites that undergo the greatest degree of isomerization correspond to disordered regions, which may have important implications on chaperone functionality within the context of aging.

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Section: Resultsmentioning

confidence: 99%

Identification of Amino Acid Epimerization and Isomerization in Crystallin Proteins by Tandem LC-MS

2014

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“…Rapid epimerization of the incubated cis ‐DKP to the trans ‐DKP was observed under all conditions. In a similar study, AA sequence inversion (α‐Asp‐Gly‐Phe) as a new thermal degradation pathway of the aspartyl tripeptide Phe‐α‐Asp‐Gly heated at 80°C in 50 mM sodium phosphate buffer, pH 7.4, was discovered by CE separation of the degradation products in the 100 mM ammonium formate BGE, pH 2.9, in 50 μm id, 62‐cm‐long FS capillary, at 30 kV, using ESI quadrupole‐TOF‐MS detection with sheath liquid consisting of water/propan‐2‐ol 1:1 v/v mixture .…”

Section: Applicationsmentioning

confidence: 99%

“…The enantiomeric and diastereomeric CE separations of peptides were systematically investigated in Scriba's group. In addition to the above (Section ) mentioned CZE separations of isomers of degradation products of aspartyl tetrapeptide Gly‐Phe‐Asp‐Gly‐OH , aspartyl tripeptide Phe‐Asp‐Gly‐OH , and its DKP derivatives, in which the resolution of co‐migrating diastereomers l ‐Phe‐α‐ l ‐Asp‐Gly‐OH and l ‐Phe‐α‐ d ‐Asp‐Gly‐OH was achieved by addition of chiral selector (16 mg/mL carboxymethyl‐β‐CD) and 5% ACN to the 50 mM sodium phosphate BGE, pH 3.0, , only two other papers were devoted to CE separation of peptide stereoisomers in the period covered by this review.…”

Section: Applicationsmentioning

confidence: 99%

Recent developments in capillary and microchip electroseparations of peptides (2011–2013)

Kašička

2013

Electrophoresis

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The review presents a comprehensive survey of recent developments and applications of capillary and microchip electroseparation methods (zone electrophoresis, ITP, IEF, affinity electrophoresis, EKC, and electrochromatography) for analysis, isolation, purification, and physicochemical and biochemical characterization of peptides. Advances in the investigation of electromigration properties of peptides, in the methodology of their analysis, including sample preseparation, preconcentration and derivatization, adsorption suppression and EOF control, as well as in detection of peptides, are presented. New developments in particular CE and CEC modes are reported and several types of their applications to peptide analysis are described: conventional qualitative and quantitative analysis, determination in complex (bio)matrices, monitoring of chemical and enzymatical reactions and physical changes, amino acid, sequence and chiral analysis, and peptide mapping of proteins. Some micropreparative peptide separations are shown and capabilities of CE and CEC techniques to provide relevant physicochemical characteristics of peptides are demonstrated.

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Capillary electrophoretic study of the degradation pathways and kinetics of the aspartyl model tetrapeptide Gly-Phe-Asp-GlyOH in alkaline solution

Brückner

Imhof

Scriba

2013

Journal of Pharmaceutical and Biomedical Analysis

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CE-MS Identification of Amino Acid Sequence Inversion as a New Degradation Pathway of an Aspartyl Model Tripeptide

Cited by 3 publications

References 21 publications

Identification of Amino Acid Epimerization and Isomerization in Crystallin Proteins by Tandem LC-MS

Identification of Amino Acid Epimerization and Isomerization in Crystallin Proteins by Tandem LC-MS

Recent developments in capillary and microchip electroseparations of peptides (2011–2013)

Capillary electrophoretic study of the degradation pathways and kinetics of the aspartyl model tetrapeptide Gly-Phe-Asp-GlyOH in alkaline solution

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