02.12.2021 - Structure and Function of Na+ and H+ dependent transporters
Na/H exchangers are a important and diverse family of secondary active transporters. These proteins are crucial in pH, sodium and volume homeostasis, dysfunction is critical in eukaryotes and procaryotes alike. In the final session of the Transporter Webinar Series David Drew and Matthias Quick share some of their research on the structure and function of this transporter family.
Title: Structure and mechanism of the Na+/H+ exchanger NHA2
David Drew, Professor in Biochemistry,
SLC9B2, also known as NHA2, correlates with the long-sought after sodium/lithium (Na+/Li+) exchanger linked to the pathogenesis of diabetes mellitus and essential hypertension in humans. Despite its functional importance, structural information and the molecular basis of its ion-exchange mechanism have been lacking. Here, we I briefly present the cryo EM structures of bison NHA2 in detergent and in nanodiscs at 3.0 and 3.5 Å resolution, respectively. I will then show how SSM-based electrophysiology has enabled us to conclude that NHA2 catalyses the electroneutral rather than electrogenic exchange of ions. The ion-binding site is quite distinctive, with a tryptophan-arginine-glutamate triad separated from the well-established ion-binding aspartates. These triad residues fine-tune ion binding specificity, as demonstrated by a salt-bridge swap mutant that converts NHA2 into a Li+-specific transporter.
Matthias Quick, Associate Professor of Neurobiology
When: Thursday December 2nd, 3 PM CET, 10 AM EDT