TY - JOUR
T1 - Nonenzymatic Posttranslational Modifications and Peptide Cleavages Observed in Peptide Epimers
AU - Long, Connor C.
AU - Antevska, Aleksandra
AU - Mast, David H.
AU - Okyem, Samuel
AU - Sweedler, Jonathan V.
AU - Do, Thanh D.
N1 - Publisher Copyright:
© 2023 American Society for Mass Spectrometry. Published by American Chemical Society. All rights reserved.
PY - 2023/9/6
Y1 - 2023/9/6
N2 - Posttranslational modifications (PTMs) play vital roles in cellular homeostasis and are implicated in various pathological conditions. This work uses two ion mobility spectrometry-mass spectrometry (IMS-MS) modalities, drift-tube IMS (DT-IMS) and trapped IMS (TIMS), to characterize three important nonenzymatic PTMs that induce no mass loss: l/d isomerization, aspartate/isoaspartate isomerization, and cis/trans proline isomerization. These PTMs are assessed in a single peptide system, the recently discovered pleurin peptides, Plrn2, from Aplysia californica. We determine that the DT-IMS-MS/MS can capture and locate asparagine deamidation into aspartate and its subsequent isomerization to isoaspartate, a key biomarker for age-related diseases. Additionally, nonenzymatic peptide cleavage via in-source fragmentation is evaluated for differences in the intensities and patterns of fragment peaks between these PTMs. Peptide fragments resulting from in-source fragmentation, preceded by peptide denaturation by liquid chromatography (LC) mobile phase, exhibited cis/trans proline isomerization. Finally, the effects of differing the fragmentation voltage at the source and solution-based denaturation conditions on in-source fragmentation profiles are evaluated, confirming that LC denaturation and in-source fragmentation profoundly impact N-terminal peptide bond cleavages of Plrn2 and the structures of their fragment ions. With that, LC-IMS-MS/MS coupled with in-source fragmentation could be a robust method to identify three important posttranslational modifications: l/d isomerization, Asn-deamidation leading to Asp/IsoAsp isomerization, and cis/trans proline isomerization.
AB - Posttranslational modifications (PTMs) play vital roles in cellular homeostasis and are implicated in various pathological conditions. This work uses two ion mobility spectrometry-mass spectrometry (IMS-MS) modalities, drift-tube IMS (DT-IMS) and trapped IMS (TIMS), to characterize three important nonenzymatic PTMs that induce no mass loss: l/d isomerization, aspartate/isoaspartate isomerization, and cis/trans proline isomerization. These PTMs are assessed in a single peptide system, the recently discovered pleurin peptides, Plrn2, from Aplysia californica. We determine that the DT-IMS-MS/MS can capture and locate asparagine deamidation into aspartate and its subsequent isomerization to isoaspartate, a key biomarker for age-related diseases. Additionally, nonenzymatic peptide cleavage via in-source fragmentation is evaluated for differences in the intensities and patterns of fragment peaks between these PTMs. Peptide fragments resulting from in-source fragmentation, preceded by peptide denaturation by liquid chromatography (LC) mobile phase, exhibited cis/trans proline isomerization. Finally, the effects of differing the fragmentation voltage at the source and solution-based denaturation conditions on in-source fragmentation profiles are evaluated, confirming that LC denaturation and in-source fragmentation profoundly impact N-terminal peptide bond cleavages of Plrn2 and the structures of their fragment ions. With that, LC-IMS-MS/MS coupled with in-source fragmentation could be a robust method to identify three important posttranslational modifications: l/d isomerization, Asn-deamidation leading to Asp/IsoAsp isomerization, and cis/trans proline isomerization.
KW - IsoAsp formation
KW - asparagine deamidation
KW - cis/trans proline isomerization
KW - mass spectrometry
KW - posttranslational modifications
UR - http://www.scopus.com/inward/record.url?scp=85156270629&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85156270629&partnerID=8YFLogxK
U2 - 10.1021/jasms.3c00092
DO - 10.1021/jasms.3c00092
M3 - Article
C2 - 37102735
AN - SCOPUS:85156270629
SN - 1044-0305
VL - 34
SP - 1898
EP - 1907
JO - Journal of the American Society for Mass Spectrometry
JF - Journal of the American Society for Mass Spectrometry
IS - 9
ER -