Extended Data Fig. 8: Ion-binding site and SSM measurements of bison NHA2 ΔN.
From: Structure, mechanism and lipid-mediated remodeling of the mammalian Na+/H+ exchanger NHA2
a. left: electrostatic surface of the NHA2ΔN ion-binding site from the detergent structure. Model is shown in cartoon representation colored as in Fig. 1c, the electrostatic surface potential is colored blue to red, for positive to negative charges, respectively. right: as in the left panel, but surface shows residue conservation, colored according to conservation scores from the alignment of representative 500 mammalian NHA2 sequences calculated usning the ConSurf server83 to highlight that the negative charges on one side of the outward-facing funnel are highly conserved. b left: Comparison between ion-binding site residues in the NHA2ΔN structure obtained in detergent and nanodiscs, with helices shown in cartoon representation and residues as sticks colored for nanodisc as in Fig. 1c, and detergent in sand. right: Cartoon representation of the ion-binding site of NHA2 in nanodiscs with the residues of the TM12a-b breakpoint illustrated in stick form to highlight the stabilization by K459 and R431, which is further salt-bridged to E214, with putative hydrogen bonds illustrated as dotted lines, as is the salt bridge. c. SSM-based electrophysiology measurements of bison NHA2ΔN proteoliposome with transient currents recorded after Li+ concentration jumps at pH 7.5 on both sides. d. As in c. Transient currents in different lipid to protein ratios as indicated.
