FIGURE 1.

Oligomeric state of the wild-type Glu³¹ stefin B samples before (A) and after (B) SPR measurements. A Superdex 75 column (GE Healthcare) was used to perform size exclusion chromatography. The column was equilibrated in phosphate buffer, pH 7.0, containing 0.15 m NaCl. The flow rate was 0.5 ml/min at room temperature. 50 μl of the Glu³¹ stefin B monomers, dimers, tetramers, and higher oligomers were injected.