Fig. 1: Crystal structure of NhaA at active pH 6.5 reveals the pH sensor is a switch to open access to ion-binding site. | Nature Communications

Fig. 1: Crystal structure of NhaA at active pH 6.5 reveals the pH sensor is a switch to open access to ion-binding site.

From: Crystal structure of the Na+/H+ antiporter NhaA at active pH reveals the mechanistic basis for pH sensing

Fig. 1

a Cartoon representation of monoLCP-NhaA. Showing the dimer domain (blue), 6TM core domain (green), pH sensing region residue (as pink sticks), and ion-binding site residues (as yellow sticks). b Cylindrical cartoon representation of NhaA from the cytoplasmic site, overlaying the pH 4.0 structure (PDB ID: 4AU5, grey) over the pH 6.5 structure (PDB ID: 7S24, colored). Movement of helices between the two structures are indicated by arrows. c Look onto the cytoplasmic pH-sensing region of EcNhaA. Residues identified to play a crucial role in pH-sensing are shown as sticks and salt-bridges indicated by a dashed line. The pH 4.0 structure (PDB ID: 4AU5, grey) is superimposed against the monoLCP-NhaA structure (coloured). d Electrostatic surface representation looking at the inside-open ion-binding funnel of EcNhaA, comparing the dimerLCP-NhaA structure (PDB ID: 4AU5) at inactive pH 4.0 (left) against the monoLCP-NhaA structure at pH 6.5 (right). Arrows indicate the rearrangements of indicated amino acids. The ion-binding funnel is marked by a black ellipsis. It notably widens at active pH.

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