Fig. 3.

Analysis of amino acid substitutions that alter gp6 oligomerization. (A) The positions of the amino acids within the intersubunit interface of gp6 (PDB ID code 3JVO) that were substituted to alter oligomerization. One monomer is shown in ribbon format, whereas neighboring subunits in the gp6 ring are depicted in surface representation. This figure was generated using PyMol (http://pymol.sourceforge.net/). (B) Gel filtration elution profiles of gp6 mutants altering oligomerization. Purified preparations of WT gp6 (blue), and the L28A (black), E89R (red), and L65D (green) mutants were each analyzed by gel filtration chromatography on a Superdex-200 column. The proteins were loaded at concentrations between 20 and 80 μM. The elution volumes were consistent with two species, a monomer and an oligomer with a stoichiometry of approximately 13.