Physicochemical Characterization of the Reassembled Dimer of an Integral Membrane Protein OmpF Porin

The in vitro reassembled species of OmpF porin, which was renatured from its denatured monomer using n-octyl-β-D-glucopyranoside, was characterized by low-angle laser light scattering photometry, circular dichroism spectroscopy and synchrotron radiation small-angle X-ray scattering measurements. The light scattering measurement reconfirmed that the reassembled species was the dimer of the protein. Circular dichroism spectra of the reassembled dimer showed a native-like β-structure. A small-angle X-ray scattering measurement indicated that the size of the reassembled dimer was nearly equal to that of the native trimer under the present experimental conditions. In a thermal denaturation experiment followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the reassembled dimer was less stable than the native trimer.