The oligomerization of M1 analyzed by gel filtration.

The oligomerization of M1 was analyzed on a Superdex 200 HR 10/30 column. (A) Purified M1 from nickel affinity chromatography yielded four peaks, whose elution volumes are indicated. The samples from each peak were collected and analyzed by SDS-PAGE. (B) The 15.8-ml fraction (from panel A) was collected, concentrated and re-applied on the gel filtration column at different concentrations, at pH 7.4. (C) Different concentrations of M1 all eluted as a single peak on the gel filtration column at pH 5.0. (D) Peak 1, 2, 3 correspond to the 10.1-ml, 11.2-ml, and 13.5-ml fractions of M1 re-applied on the gel filtration column at pH 7.4, respectively. Peak 4 corresponds to the 11.2-ml fraction re-applied on the gel filtration column at pH 5.0.