Protein Conformational Exchanges Modulated by the Environment of Outer Membrane Vesicles

Protein function, in many cases, is strongly coupled to the dynamics and conformational equilibria of the protein. The environment surrounding proteins is critical for their dynamics and can dramatically affect the conformational equilibria and subsequently the activities of proteins. However, it is unclear how protein conformational equilibria are modulated by their crowded native environments. Here we reveal that outer membrane vesicle (OMV) environments modulate the conformational exchanges of Im7 protein at its local frustrated sites and shift the conformation toward its ground state. Further experiments show both macromolecular crowding and quinary interactions with the periplasmic components stabilize the ground state of Im7. Our study highlights the key role that the OMV environment plays in the protein conformational equilibria and subsequently the conformation-related protein functions. Furthermore, the long-lasting nuclear magnetic resonance measurement time of proteins within OMVs indicates that they could serve as a promising system for investigating protein structures and dynamics in situ via nuclear magnetic spectroscopy.

Automated summary

Protein function is closely related to its dynamics and conformational equilibria. The environment surrounding proteins is critical for their dynamics and can significantly affect the conformational equilibria and protein activities. This study reveals that the outer membrane vesicle (OMV) environment modulates the conformational exchanges of Im7 protein and shifts it towards its ground state. Furthermore, this research highlights the key role of the OMV environment in protein conformational equilibria and subsequent protein functions. The long-lasting nuclear magnetic resonance measurement time of proteins within OMVs suggests their potential for studying protein structures and dynamics in situ using nuclear magnetic spectroscopy.