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Characterisation of the heptameric pore‐forming complex of the Aeromonas toxin aerolysin using MALDI‐TOF mass spectrometry
Author(s) -
Moniatte M.,
van der Goot F.G.,
Buckley J.T.,
Pattus F.,
van Dorsselaer A.
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(96)00328-6
Subject(s) - aerolysin , mass spectrometry , chemistry , oligomer , matrix assisted laser desorption/ionization , pore forming toxin , crystallography , chromatography , biophysics , toxin , microbial toxins , biochemistry , biology , desorption , polymer chemistry , virulence , organic chemistry , adsorption , gene
Aerolysin, a virulence factor secreted by Aeromonas hydrophila , is representative of a group of β‐sheet toxins that must form stable homooligomers in order to be able to insert into biological membranes and generate channels. Electron microscopy and image analysis of two‐dimensional membrane crystals had previously revealed a structure with 7‐fold symmetry et al. (1992) EMBO J. 11, 2457–2463]. However, this unusual et al. (1992) EMBO J. 11, 2457–2463]. However, this unusual molecularity of the channel remained to be confirmed by an independent method since low‐resolution electron crystallography had led to artefactual data for other pore‐forming toxins. In this study, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF‐MS) was used to measure the mass of the aerolysin oligomer preparation. A mass of 333 850 Da was measured, fitting very well with a heptameric complex (expected mass: 332 300 Da). These results confirm the earlier evidence that the aerolysin oligomer is a heptamer and also show that MALDI‐TOF mass spectrometry could be a valuable tool to study non‐covalent association of proteins.