Monitoring the stabilities of a mixture of peptides by mass-spectrometry-based techniques.
Eur J Mass Spectrom (Chichester)
; 25(1): 73-81, 2019 Feb.
Article
em En
| MEDLINE
| ID: mdl-30773926
ABSTRACT
Biomolecular degradation plays a key role in proteostasis. Typically, proteolytic enzymes degrade proteins into smaller peptides by breaking amino acid bonds between specific residues. Cleavage around proline residues is often missed and requires highly specific enzymes for peptide processing due to the cyclic proline side-chain. However, degradation can occur spontaneously (i.e. in the absence of enzymes). In this study, the influence of the first residue on the stability of a series of penultimate proline containing peptides, with the sequence Xaa-Pro-Gly-Gly (where Xaa is any amino acid), is investigated with mass spectrometry techniques. Peptides were incubated as mixtures at various solution temperatures (70â to 90â) and were periodically sampled over the duration of the experiment. At elevated temperatures, we observe dissociation after the Xaa-Pro motif for all sequences, but at different rates. Transition state thermochemistry was obtained by studying the temperature-dependent kinetics and although all peptides show relatively small differences in the transition state free energies (â¼95 kJ/mol), there is significant variability in the transition state entropy and enthalpy. This demonstrates that the side-chain of the first amino acid has a significant influence on the stability of the Xaa-Pro sequence. From these data, we demonstrate the ability to simultaneously measure the dissociation kinetics and relative transition state thermochemistries for a mixture of peptides, which vary only in the identity of the N-terminal amino acid.
Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Peptídeos
/
Espectrometria de Massas
Tipo de estudo:
Evaluation_studies
Idioma:
En
Revista:
Eur J Mass Spectrom (Chichester)
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Estados Unidos