Open AccessBinding of a paramagnetic metal cation to Escherichia coli K‐12 outer‐membrane vesicles
Author(s) -
Ferris F.G.,
Beveridge T.J.
Publication year - 1984
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1984.tb01241.x
Subject(s) - vesicle , chemistry , crystallography , bilayer , bacterial outer membrane , lipid bilayer , electron paramagnetic resonance , membrane , paramagnetism , europium , nuclear magnetic resonance spectroscopy , metal , spectroscopy , escherichia coli , nuclear magnetic resonance , stereochemistry , ion , biochemistry , organic chemistry , physics , quantum mechanics , gene
Outer‐membrane vesicles from Escherichia coli K‐12 produced typical phosphorus nuclear magnetic resonance ( 31 P‐NMR) spectra that were indicative of a lipid bilayer conformation. Upon the addition of the paramagnetic cation Eu III, spectra were broadened and shifted illustrating a direct interaction between the phosphoryl groups of the constituent outer‐membrane (OM) molecules and the metal cation. The extent of the broadening, however, was atypical for Eu III and suggestive of a restriction in molecular motion within the OM vesicles. Bound europium (Z = 63) produced enough electron contrast for low‐dose electron microscopic imaging and was also detected by energy‐dispersive X‐ray spectroscopy (EDS). Small electron‐dense precipitates were associated with the OM vesicles and could be stable, neutrally charged, water‐insoluble co‐ordination complexes.