Fig. 3. (A) The thermostability of the NHR-trimers at a concentration of 10 μM in PBS was determined using CD spectroscopy. (B)–(D) Increased thermal tolerance of isopeptide bridge-tethered N-trimers. A mixture of crosslinked N-trimers and their uncrosslinked counterparts (1 : 3 molar ratio) was heated at the indicated temperature for 10 min, centrifuged, and the supernatant was analyzed using RP-HPLC.