Figure 3.

Analysis of the quaternary structure of WT and mutant DENV2C proteins by gel-filtration chromatography using a TSK3000SWXL column. Chromatography was performed at 25 °C in 50 mM sodium phosphate buffer (pH 6.0) containing 0.2 mM NaCl and 0.05% NaN₃ at a flow rate of 1 mL/min for a duration of 20 min. The injection volume was 200 µL. The protein elution was monitored by a fluorescence detector with excitation at 280 nm and emission at 340 nm. (A) Injection of a mixture of standard proteins containing thyroglobulin (Thyr), apoferritin (Apo), β-amylase (β-amyl), bovine serum albumin (BSA), ovalbumin (Ova), chymotrypsinogen A (Chymo-A), Aprotinin (Aprot) and N-acetyl-L-tryptophan (N-Ac-L-Tryp). (B) Calibration curve obtained by plotting the elution volume of the standard proteins versus the logarithm of the molecular weight (MW). (C–E), (F,G) show the injection of 200 µL of 30 µM DENV2C (WT) and single mutants L50S, L54S, L81N and I88N, respectively.