Figure 4.

A dynamic hydrophobic pocket is essential for stomatin function. (A) Lipophilic surface potential of stomatin^86–213 where hydrophobic residues are indicated in green and polar residues in yellow. A hydrophobic pocket is filled by residues Leu91 and Ile92 of an opposing monomer. (B) Structural rearrangements in α1, α2 and β2 induce pocket closure, as seen by a superposition of the open (orange) and closed (white) pocket structures. (C) In stomatin^86–213 LI91,92AA, the pocket is partially closed. (D) CD measurements for stomatin^86–213 (red) and the LI91,92AA (blue) and T182W mutants (black). (E) Analytical gel filtration experiments for the indicated stomatin^86–213 mutants. (F) Electrophysiological recordings of CHO cells co-transfected with ASIC3 and the indicated stomatin constructs at pH 4.0 and pH 6.0, as described in Figure 3A. (G) Inactivation times for CHO cells transfected with ASIC2a and the indicated stomatin constructs as described in Figure 3C.