Variable-Temperature ESI-IMS-MS Analysis of Myohemerythrin Reveals Ligand Losses, Unfolding, and a Non-Native Disulfide Bond.

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 ∼15 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 ∼15 to 35 °C, some bound oxygen dissociates; at ∼66 °C, the cofactor dissociates to produce populations of both folded and unfolded apoprotein. At higher temperatures (∼85 °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

SUBMITTER: Woodall DW 

PROVIDER: S-EPMC6935875 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature