Figure 7.

Pherophorin-DZ1 Polymerization Assay after Size-Exclusion Chromatography in the Presence of 6 M Guanidinium Hydrochloride.

Sixty micrograms of purified ³³P-labeled pherophorin-DZ1 was applied to a Superose 12 column (bed volume, 24 mL; Amersham Pharmacia Biotech) equilibrated in 6 M guanidinium hydrochloride and 100 mM sodium phosphate, pH 7.0. Pherophorin-DZ1 eluted with the void volume (V₀) of 7 mL. The peak fraction was dialyzed against Volvox medium and concentrated fivefold by ultrafiltration. Twenty-microliter aliquots then were incubated for 6 hr at 28°C in the presence or absence of 1 mM DTT. Both samples were analyzed by SDS-PAGE followed by fluorography. The insert shows incubation in the absence (lane 1) or presence (lane 2) of DTT.