*4.8. SEC*

SEC experiments were performed at pH 8.0 (50 mM Tris) and 0.250 M NaCl in a Superose 12 10/300 GL column, which was connected to an AKTA FPLC (GE Healthcare, Barcelona, Spain); absorbance at 280 nm was monitored during the elution. Flow rate was 0.8 mL/min, and C-LrtA was loaded in a volume of 100 μL at several protein concentrations, in the range of 30–500 μM (in protomer concentration). The markers used to calibrate the column were ferritin, catalase, aldolase, albumin, bovine RNase A and blue dextran (GE Healthcare, Barcelona, Spain); the isolated protein markers were loaded in the column in the above described buffer, at the same flow rate, and three independent measurements were performed with each marker.
