Open AccessEvidence for the Supramolecular Organization of a Bacterial Outer-Membrane Protein from In Vivo Pulse Electron Paramagnetic Resonance Spectroscopy
Author(s) -
David A. Nyenhuis,
Thushani D. Nilaweera,
Jessica K. Niblo,
Nhu Nguyen,
Kateri H. DuBay,
David S. Cafiso
Publication year - 2020
Publication title -
journal of the american chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.115
H-Index - 612
eISSN - 1520-5126
pISSN - 0002-7863
DOI - 10.1021/jacs.0c01754
Subject(s) - chemistry , bacterial outer membrane , site directed spin labeling , electron paramagnetic resonance , membrane , biophysics , electron transport chain , pulsed epr , membrane protein , force spectroscopy , monomer , crystallography , biochemistry , molecule , escherichia coli , nuclear magnetic resonance , spin echo , gene , biology , polymer , radiology , medicine , physics , organic chemistry , magnetic resonance imaging
In the outer membrane of Gram-negative bacteria, membrane proteins are thought to be organized into domains or islands that play a role in the segregation, movement, and turnover of membrane components. However, there is presently limited information on the structure of these domains or the molecular interactions that mediate domain formation. In the present work, the Escherichia coli outer membrane vitamin B 12 transporter, BtuB, was spin-labeled, and double electron-electron resonance was used to measure the distances between proteins in intact cells. These data together with Monte Carlo simulations provide evidence for the presence of specific intermolecular contacts between BtuB monomers that could drive the formation of string-like oligomers. Moreover, the EPR data provide evidence for the location of the interacting interfaces and indicate that lipopolysaccharide mediates the contacts between BtuB monomers.