Mechanisms of Peptide Fragmentation from Time-and Energy-Resolved Surface-Induced Dissociation Studies: Dissociation of Angiotensin Analogs

Journal Article · Wed Mar 01 04:00:00 EST 2006 · International Journal of Mass Spectrometry

DOI:https://doi.org/10.1016/j.ijms.2005.11.007· OSTI ID:881090

Laskin, Julia; Bailey, Thomas H; Futrell, Jean H

Energetics and mechanism of dissociation of singly protonated angiotensin III (RVYIHPF) and its analogs RVYIFPF, RVYIYPF, RVYIHAF, and RVYIHDF was studied using surface-induced dissociation (SID) in a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR MS) specially configured for studying ion activation by collisions with surfaces. The energetics and dynamics of peptide fragmentation were deduced by modeling the time- and energy-resolved survival curves for each precursor ion using an RRKM based approach developed in our laboratory. Fragmentation mechanisms were inferred from comparison of time- and energy-resolved fragmentation efficiency curves (TFECs) of different fragment ions followed by RRKM modeling of dissociation of angiotensin III into six major families of fragment ions. Detailed modeling demonstrated that dissociation of these peptides is dominated by loss of ammonia from the precursor ion and characterized by a high energy barrier of 1.6 eV. Loss of NH3 and subsequent rearrangement of the MH-NH3 ion results in proton mobilization and release of ca. 30 kcal/mol into internal excitation of the MH-NH3 ion. The resulting highly excited ion accesses a variety of non-specific dissociation pathways with very high rate constants. Fast fragmentation of excited MH-NH3 ion forms a variety of abundant bn-NH3 and an-NH3 fragment ions. Abundant XH and HX internal fragments are also formed, reflecting the stability of histidine-containing diketopiperazine structures.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 881090
• Report Number(s): PNNL-SA-46740; 13301; KC0302020
• Journal Information: International Journal of Mass Spectrometry, Journal Name: International Journal of Mass Spectrometry Vol. 249-250
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
AMMONIA
ANGIOTENSIN
DISSOCIATION
EFFICIENCY
EXCITATION
Environmental Molecular Sciences Laboratory
FRAGMENTATION
ION CYCLOTRON-RESONANCE
MASS SPECTROMETERS
PEPTIDES
PRECURSOR
PROTONS
SIMULATION
STABILITY
SURVIVAL CURVES