Integration and analysis of the effects of an unnatural amino acid into transmembrane 4 of the Orai1 protein

Abstract

In this work intramolecular interactions of the Orai1 protein are investigated by integrating the unnatural amino acid p-Azido-L-phenylalanine (Azi) at different positions (A254, V252 and G247) of the Orai's transmembrane domain 4 (TM4). The compound Azi is unreactive under physiological conditions but can be activated using UV-light. Being reactive it can form covalent bonds with nearby residues. It is suspected that that residue A254 on TM4 is close enough to TM3 for the Azi to cross-link these two transmembrane domains. Positions V252 and G247 are assumed to be too far apart for crosslinking.