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

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 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.

published proceedings

  • Anal Chem

altmetric score

  • 1.25

author list (cited authors)

  • Woodall, D. W., El-Baba, T. J., Fuller, D. R., Liu, W., Brown, C. J., Laganowsky, A., Russell, D. H., & Clemmer, D. E.

citation count

  • 19

complete list of authors

  • Woodall, Daniel W||El-Baba, Tarick J||Fuller, Daniel R||Liu, Wen||Brown, Christopher J||Laganowsky, Arthur||Russell, David H||Clemmer, David E

publication date

  • May 2019