Linking function to global and local dynamics in an elevator-type transporter. Academic Article uri icon

Overview

abstract

  • Transporters cycle through large structural changes to translocate molecules across biological membranes. The temporal relationships between these changes and function, and the molecular properties setting their rates, determine transport efficiency-yet remain mostly unknown. Using single-molecule fluorescence microscopy, we compare the timing of conformational transitions and substrate uptake in the elevator-type transporter GltPh We show that the elevator-like movements of the substrate-loaded transport domain across membranes and substrate release are kinetically heterogeneous, with rates varying by orders of magnitude between individual molecules. Mutations increasing the frequency of elevator transitions and reducing substrate affinity diminish transport rate heterogeneities and boost transport efficiency. Hydrogen deuterium exchange coupled to mass spectrometry reveals destabilization of secondary structure around the substrate-binding site, suggesting that increased local dynamics leads to faster rates of global conformational changes and confers gain-of-function properties that set transport rates.

publication date

  • December 7, 2021

Research

keywords

  • Amino Acid Transport System X-AG
  • Archaeal Proteins
  • Cell Membrane
  • Deuterium Exchange Measurement

Identity

PubMed Central ID

  • PMC8670510

Scopus Document Identifier

  • 85120846999

Digital Object Identifier (DOI)

  • 10.1073/pnas.2025520118

PubMed ID

  • 34873050

Additional Document Info

volume

  • 118

issue

  • 49