Barry R, Moore S, Alonso A, Ausió J, Buckley J T
Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8W 3P6, Canada.
J Biol Chem. 2001 Jan 5;276(1):551-4. doi: 10.1074/jbc.M008097200.
Proaerolysin, the proform of the channel-forming protein aerolysin, is secreted as a dimer by Aeromonas sp. The protein also exists as a dimer in the crystal, as well as in solution, at least at concentrations in the region of 500 microg/ml. Recently it has been argued that proaerolysin becomes monomeric at concentrations below 100 microg/ml and that only the monomeric form of the protoxin can bind to cell surface receptors (Fivaz, M., Velluz, M.-C., and van der Goot, F. G. (1999) J. Biol. Chem. 274, 37705-37708). Here we show, using non-denaturing polyacrylamide electrophoresis, chemical cross-linking, and analytical ultracentrifugation, that proaerolysin remains dimeric at the lowest concentrations of the protein that we measured (less than 5 microg/ml) and that the dimeric protoxin is quite capable of receptor binding.
气单胞菌溶血素原（通道形成蛋白气单胞菌溶血素的前体形式）由气单胞菌属作为二聚体分泌。该蛋白在晶体中以及在溶液中也以二聚体形式存在，至少在浓度为500微克/毫升左右时如此。最近有人认为，气单胞菌溶血素原在浓度低于100微克/毫升时会变成单体，并且只有原毒素的单体形式才能与细胞表面受体结合（Fivaz, M., Velluz, M.-C., and van der Goot, F. G. (1999) J. Biol. Chem. 274, 37705 - 37708）。在此我们通过非变性聚丙烯酰胺电泳、化学交联和分析超速离心表明，在我们测量的该蛋白最低浓度（低于5微克/毫升）下气单胞菌溶血素原仍保持二聚体形式，并且二聚体原毒素完全能够与受体结合。
