Estimation of molecular weights of membrane proteins in the presence of SDS by low-angle laser light scattering combined with high-performance porous silica gel chromatography. Confirmation of the trimer structure of porin of the E. coli outer membrane.

An assessment study was carried out to evaluate the performance of the low-angle laser light-scattering technique combined with high-performance porous silica gel chromatography in the presence of sodium dodecyl sulfate and precision differential refractometry. It was found that the combined technique is highly promising as a reliable method for determining the molecular weight of a membrane protein solubilized by the surfactant. As a test, molecular weights of porin forming the permeability channel of the outer membrane of E. coli B in an oligomeric form were measured before and after heat treatment, which is known to cause dissociation. The results obtained indicate that the porin oligomer is a trimer with stoichiometric composition.