Investigation of Factors that Trigger Essential Conformational Changes in FTT258

FTT258 is a close bacterial relative of human acyl protein thioesterase (hAPT), a protein linked to cancer. hAPT removes long chain lipids from key cancer signaling proteins. Removal of these lipids requires their insertion into a pocket within hAPT, which is only exposed after the movement of a flexible loop, a common feature between hAPT and FTT258. However, the causes for the movement of this loop are unknown. I investigated factors that may trigger loop movement in APTs like hAPT and FTT258. In particular, I exposed FTT258 to inhibitors structurally similar to long chain lipids and to membrane-mimicking surfactants in order to determine if these factors induce loop movement. Loop movement was detected by measuring the change in intrinsic tryptophan fluorescence before and after exposure to these conditions. Ultimately, understanding the factors controlling FTT258 and hAPT function can provide novel mechanisms for inhibiting cancer progression