Figure 7.

Anion exchange chromatography and LPS removal via filtration recovers 2′3’-cGAMP as the purified product. (A) The chromatogram plotting volume (mL) against Absorbance (mAU at 256 nm) and NaCl concentration (mM) shows the overall anion exchange chromatography process for purifying cGAMP. The cGAMP-containing supernatant from the microbial cell culture was diluted and loaded onto the anion exchange column, and finally eluted with increasing concentrations of NaCl. (B) The yield of the cGAMP in the different fractions of anion exchange chromatography was measured using HPLC (256 nm). (C) Representative HPLC chromatograms (256 nm) of cGAMP within the different fractions from the anion exchange chromatography. (D) Quantification of LPS in the AEX fractions was determined using the Pierce Endotoxin kit. * Bar plots show the average measurement done over three replicates (N = 3) and the error bars show the SEM. Statistical significance indicated by (*) was performed for dataset comparisons using unpaired, two-tailed t-test and Welch’s correction.