The archaeal glutamate transporter homologue GltPh shows heterogeneous substrate binding.

ABSTRACT: Integral membrane glutamate transporters couple the concentrative substrate transport to ion gradients. There is a wealth of structural and mechanistic information about this protein family. Recent studies of an archaeal homologue, GltPh, revealed transport rate heterogeneity, which is inconsistent with simple kinetic models; however, its structural and mechanistic determinants remain undefined. Here, we demonstrate that in a mutant GltPh, which exclusively populates the outward-facing state, at least two substates coexist in slow equilibrium, binding the substrate with different apparent affinities. Wild type GltPh shows similar binding properties, and modulation of the substate equilibrium correlates with transport rates. The low-affinity substate of the mutant is transient following sub

SUBMITTER: Reddy KD 

PROVIDER: S-EPMC9044058 | biostudies-literature | 2022 May

REPOSITORIES: biostudies-literature