• Nanion Technologies: イオンチャネル研究のスマートツール

    Nanion Technologies: イオンチャネル研究のスマートツール

  • SyncroPatch 384i: HTS Automated Patch Clamp

    SyncroPatch 384i: HTS Automated Patch Clamp

  • SURFE²R 96SE: ラベルフリーのトランスポーターHTS

    SURFE²R 96SE: ラベルフリーのトランスポーターHTS

  • Dynamic Clamp: Patchliner

    Dynamic Clamp: Patchliner

  • 脂質二分子膜実験: Orbitシリーズ

    脂質二分子膜実験: Orbitシリーズ

  • CardioExcyte 96 SOL: 心筋の光ペーシング

    CardioExcyte 96 SOL: 心筋の光ペーシング

Our Product Portfolio

SyncroPatch 384

SyncroPatch 384

Patchliner

Patchliner

Port-a-Patch

Port-a-Patch

Port-a-Patch mini

Port-a-Patch mini

CardioExcyte 96

CardioExcyte 96

FLEXcyte 96

FLEXcyte 96

SURFE²R 96SE

SURFE²R 96SE

SURFE²R N1

SURFE²R N1

Orbit 16 TC

Orbit 16 TC

Orbit Mini

Orbit Mini

Vesicle Prep Pro

Vesicle Prep Pro

2017 - Variations on the Coupling Theme in Secondary Active Transport

Icon N1   SURFE²R N1 Oral Presentation

Presenter: 
Gregor Madej, University of Regensburg, Germany

Source:
Nanion User Meeting
October 26.-26., 2018


Abstract:

University of Regensburg, Institute of Biophysics and Physical Biochemistry, Regensburg, Germany Numerous physiological processes, i.e. cellular uptake of glucose or hyperosmotic stress response, require specialized proteins that utilize electrochemical membrane potential as an energy source for substrate transport across the cellular membranes. One fundamentally important problem for understanding the mechanism of such secondary active transport is the relationship between binding of the cargo and the coupling ion. Typical of many secondary active transporters is
their selectivity for the coupling ion. In the symporter BetP from Corynebacterium glutamicum, which is a highly effective osmoregulated uptake system for glycine betaine, transport is coupled to the symport of two Na+ ions. Mutations, which affect residues in the Na1 site, were designed to alter its ion specificity. Here a variant BetP has been generated that couples the charge translocation also with K+. For the unrelated sugar/H+ symporter of the major facilitator superfamily (MFS), it has been shown that the affinity for the coupling ion changes during the transport cycle. In lactose  ermease from E. coli (LacY), the poster child of the MFS, sidechains have been identified modulating the pKa of the sugar-binding. However, these positions are not in direct contact to the sugar- or the H+-binding site, and are not conserved in distant MFS sugar transporters; therefore, mechanistic conclusions are difficult to draw. Here we designed mutations near the H+-
binding site in a glucose/H+ symporter GlcP of Staphylococcus epidermidis to alter the affinity for H+. We show experimental results verifying that polarity modification in the vicinity of the H+-binding site results in pKa modulation of the sugar-induced charge transfer.

M.G. Madej, K. Kossmann and C. Ziegler

Back

We use cookies on our website. Some of them are essential for the operation of the site, while others help us to improve this site and the user experience (tracking cookies). You can decide for yourself whether you want to allow cookies or not. Please note that if you reject them, you may not be able to use all the functionalities of the site.