Expression of recombinant wheat PDI family proteins. Recombinant TaPDIL1Aα (A), TaPDIL1B (B), TaPDIL2 (C), TaPDIL3A (D), TaPDL4D (E), and TaPDIL5A (F) were expressed in E. coli. cells transformed with each expression plasmid and incubated with 0.4 mM IPTG at 30°C for 0 (lane 1) or 20 h (lane 2). Soluble (lane 3) and insoluble (lane 4) fractions were separated from these cells after 20 h by centrifugation after sonication. Each recombinant PDI family protein (arrowheads) was purified by His-tag column chromatography (lane 5) followed by gel filtration chromatography (lane 6). Proteins in each sample were separated by SDS-PAGE and stained with Coomassie Brilliant Blue. (G) The CD spectra of the purified recombinant TaPDIL1Aα (●), TaPDIL1B (○), TaPDIL2 (▲), TaPDIL3A (■), TaPDL4D (♦), and TaPDIL5A (Δ) were determined at a concentration of 0.3 mg/ml. (H) The purified recombinant TaPDIL1Aα (lane 1), TaPDIL1B (lane 2), TaPDIL2 (lane 3), TaPDIL3A (lane 4), TaPDIL4D (lane 5), or TaPDIL5A (lane 6) was detected by western blot analysis with anti-TaPDIL1Aα serum (lanes 1 and 2), anti-TaPDIL2 serum (lane 3), anti-TaPDIL3A serum (lane 4), anti-TaPDIL4D serum (lane 5), or anti-TaPDIL5A serum (lane 6). Asterisks indicate degradation products.