Figure 1.

Stradomers form highly ordered multimers, which can be fractionated by size. (A) Stradomers consist of the murine IgG2a hinge, CH2, and CH3 domains (abbreviated as 2A), linked to a multimerization domain (MD) at the carboxy (C) or amino (N) terminus. The MD is either the human IgG2 hinge (2H) or an isoleucine zipper (ILZ). (B) SDS-PAGE of the stradomer proteins. Homodimeric 2A-2H_C bands have a molecular mass of 55 kDa. Multimeric bands have a mass of 150 kDa or more. (C) The 2A-2H_C protein was fractionated on a GE Highload Phenyl Sepharose High-Performance column (GE 17-1066-01) by using a standard protocol. The sample was run at a rate of 3 ml/min, and 2-ml fractions were collected. UV spectrometry at 280 nm was used to quantify protein in each fraction, yielding a histogram readout characterized by peaks representing the different fractions. (D) SDS-PAGE of unfractionated 2A-2H_C, fraction I, fraction II, and fraction III. Homodimeric 2A-2H_C bands have a mass of 55 kDa. Multimeric bands are higher at ≥ 100 kDa.