[NMR paper] High-resolution in-situ NMR spectroscopy of bacterial envelope proteins in outer membrane vesicles.

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High-resolution in-situ NMR spectroscopy of bacterial envelope proteins in outer membrane vesicles.

Related Articles High-resolution in-situ NMR spectroscopy of bacterial envelope proteins in outer membrane vesicles.

Biochemistry. 2020 Apr 01;:

Authors: Thoma J, Burmann BM

Abstract
The cell envelope of Gram-negative bacteria is an elaborate cellular environment, consisting of two lipid membranes separated by the aqueous periplasm. So far, efforts to mimic this environment under laboratory conditions were limited by the complexity of the asymmetric bacterial outer membrane. To evade this impasse, we recently established a method to modify the protein composition of bacterial outer membrane vesicles (OMVs) released from Escherichia coli (E. coli) as a platform for biophysical studies of outer membrane proteins in their native membrane environment. Here, we apply protein-enriched OMVs to characterize the structure of three envelope proteins from E. coli using nuclear magnetic resonance (NMR) spectroscopy and expand the methodology to soluble periplasmic proteins. We obtain high-resolution in-situ NMR spectra of the transmembrane protein OmpA as well as the periplasmic proteins CpxP and MalE. We find that our approach facilitates structural investigations of membrane-attached protein domains and is especially suited for soluble proteins within in their native periplasmic environment. Thereby, the use of OMVs in solution NMR-methods allows in-situ analysis of the structure and dynamics of proteins twice the size compared to current in-cell NMR methodology. We therefore expect our work to pave the way for more complex NMR studies of bacterial envelope proteins in the native environment of OMVs in the future.


PMID: 32233422 [PubMed - as supplied by publisher]



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