Concentration, not temperature or IP6, is the primary driver of tetramerization.

A. SEC chromatograms of MBPCC1 at 4˚, 24˚, and 32˚C. The instrument and column for T = 24˚C and T = 32˚C were the same (Superdex 200 Increases run on a Shimadzu system), but different from sample injected at 4C (Superdex 200 column and Akta Explorer). Both peaks are at molecular weights consistent with tetrameric protein at all temperatures tested. B and C. Protein at different concentrations (250 μM, 125 μM, 62.5 μM, 31.25 μM, 15.625 μM, and 7.8125 μM) was injected at 24˚C in the absence (B) and presence (C) of IP6. Insets show the normalized absorbance to highlight the shift in elution volume at lower concentrations. (D) Fraction of tetramer vs concentration (n = 3 for each concentration).