Surface plasmon resonance analysis of the interaction between sERGIC-53 and MCFD2. (A) sERGIC-53 (10 μg/mL) was injected (at t = 0) over the sensor chip on which MCFD2 was immobilized by amine coupling. The injection of sERGIC-53 was stopped at 90 seconds. (B) sERGIC-53, sVIP36, and sVIPL (all at a concentration of 10 μg/mL) were injected over the sensor chip on which MCFD2 was immobilized in the presence of 1 mM CaCl₂. (C) In the presence of 1 mM CaCl₂, sERGIC-53 (10 μg/mL) was injected over sensor chips on which MCFD2 or its mutants were immobilized.