Figure 3.

Trp fluorescence of unmyristoylated proteins. (A) Myristoylated Gα_t (native) is enzymatically cleaved at the N-terminus to yield the unmyristoylated ΔNT Gα_t protein used in structure determination.⁶ (B) Emission of 500 nM ΔNT-Gα_t protein was scanned as above before (dotted line) and after (solid) activation with AlF₄ as in Figure 1. Control, inset: ΔNT-Gα_t demonstrated ≥40% increase in Trp fluorescence upon AlF₄ activation. (C) Summary of em_max before and after activation for indicated Gα proteins (n ≥ 3, ±SEM; statistically significant changes noted by asterisk(s), ***P < 0.001, **P < 0.01). Dark gray bars, far left, Gα_i; light gray, center, Gα_i HI; black, far right, ΔNTGα_t.