The SPR2 C-terminal domain is monomeric.

A) SECMALS analysis of the purified SPR2 649–864 construct (full-length FW: 24.2 kDa). Plot shows the elution profile from the size exclusion column as measured using the refractive index (y-axis at right) over time. The experimentally determined mass is plotted in kDa (MW, y-axis at left) over time across the elution peak. The average mass (± standard deviation) is indicated. The dashed gray line indicates the monomeric formula weight of a full-length construct (24.2 kDa). B) Coomassie-stained SDS PAGE (15%) analysis of purified native (not SeMet-substituted) and SeMet-substituted SPR2 C-terminal domain constructs, and harvested SeMet-substituted SPR2 crystals. Molecular weight marker (MWM) standards are indicated.