1.
Phys Chem Chem Phys
; 17(7): 4875-8, 2015 Feb 21.
Artigo
em Inglês
| MEDLINE
| ID: mdl-25613578
RESUMO
We report on the application of site-directed spin labeling (SDSL) and electron paramagnetic resonance (EPR) spectroscopy to study possible oligomerization of the bacterial toxin colicin A (ColA) upon membrane insertion in vitro and in vivo. We applied SDSL-EPR protocols and optimized experimental conditions to perform continuous wave EPR experiments and double electron-electron resonance distance measurements on intact Escherichia coli cells interacting with nitroxide spin-labeled ColA. Our data suggest that ColA forms dimers upon membrane insertion, thus explaining previously reported pore diameters of about 1 nm, which are unlikely to be formed by a single colicin A monomer.