Chemical synthesis of H2 relaxin analogue carrying an affinity tag through click chemistry-assisted diaminodiacid strategy

H2 relaxin is an important member of the insulin superfamily, but little is known about how H2-relaxin activates the RXFP1 receptor. Affinity-tag containing peptide probes could separate receptor from cell/tissue lysate through pull-down methods, and the probe-receptor complex could be applied in the structure resolution to understand the receptors activate mechanism. The affinity-tag modified H2 relaxin probe has about 70-residue, it was very difficult to obtain through our previous diaminodiacid (DADA) based single-shot solid-phase synthesis strategy. Here we report a click chemistry-assisted single-shot solid-phase synthesis strategy for the synthesis of H2 relaxin probe bearing affinity-purified tags. This study highlights the utility of modern chemical protein synthesis in obtaining custom designed tools for biological studies.