UN2A undergoes a pH-dependent conformational change. CD was used to measure the secondary structure of UN2A at a pH range from 4.0 to 8.0. (A) Representative CD spectra of UN2A over a range of pHs from 200 to 250 nm. As can be seen, the minima at 208 and 222 nm become deeper as the pH decreases, consistent with helical content at lower pHs. (B) The average mdeg signal at 222 nm was plotted as a function of pH for N = 4 trials. There is a slight decrease in the average signal between pH 8 and 6 with a more significant shift occurring below pH 6.