Variable-Temperature ESI-IMS-MS Analysis of Myohemerythrin Reveals Ligand Losses, Unfolding, and a Non-Native Disulfide Bond.
Anal Chem
; 91(10): 6808-6814, 2019 05 21.
Article
em En
| MEDLINE
| ID: mdl-31038926
ABSTRACT
Variable-temperature electrospray ionization combined with ion mobility spectrometry (IMS) and mass spectrometry (MS) techniques are used to monitor structural transitions of the protein myohemerythrin from peanut worm in aqueous ammonium acetate solutions from â¼15 to 92 °C. At physiological temperatures, myohemerythrin favors a four-helix bundle motif and has a diiron oxo cofactor that binds oxygen. As the solution temperature is increased from â¼15 to 35 °C, some bound oxygen dissociates; at â¼66 °C, the cofactor dissociates to produce populations of both folded and unfolded apoprotein. At higher temperatures (â¼85 °C and above), the IMS-MS spectrum indicates that the folded apoprotein dominates, and provides evidence for stabilization of the structure by formation of a non-native disulfide bond. In total, we find evidence for 18 unique forms of myohemerythrin as well as information about the structures and stabilities of these states. The high-fidelity of IMS-MS techniques provides a means of examining the stabilities of individual components of complex mixtures that are inaccessible by traditional calorimetric and spectroscopic methods.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Helminto
/
Hemeritrina
Limite:
Animals
Idioma:
En
Ano de publicação:
2019
Tipo de documento:
Article