Structural and functional insights into the interaction and targeting hub TMD0 of the polypeptide transporter TAPL

  • The ATP-binding cassette transporter TAPL translocates polypeptides from the cytosol into the lysosomal lumen. TAPL can be divided into two functional units: coreTAPL, active in ATP-dependent peptide translocation, and the N-terminal membrane spanning domain, TMD0, responsible for cellular localization and interaction with the lysosomal associated membrane proteins LAMP-1 and LAMP-2. Although the structure and function of ABC transporters were intensively analyzed in the past, the knowledge about accessory membrane embedded domains is limited. Therefore, we expressed the TMD0 of TAPL via a cell-free expression system and confirmed its correct folding by NMR and interaction studies. In cell as well as cell-free expressed TMD0 forms oligomers, which were assigned as dimers by PELDOR spectroscopy and static light scattering. By NMR spectroscopy of uniformly and selectively isotope labeled TMD0 we performed a complete backbone and partial side chain assignment. Accordingly, TMD0 has a four transmembrane helix topology with a short helical segment in a lysosomal loop. The topology of TMD0 was confirmed by paramagnetic relaxation enhancement with paramagnetic stearic acid as well as by nuclear Overhauser effects with c6-DHPC and cross-peaks with water.

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Author:Christoph Bock, Frank LöhrORCiD, Franz Tumulka, Katrin Reichel, Julia Würz, Gerhard HummerORCiD, Lars Schäfer, Robert TampéORCiDGND, Benesh Joseph, Frank BernhardORCiD, Volker DötschORCiDGND, Rupert Abele
Pubmed Id:
Parent Title (English):Scientific reports
Publisher:Macmillan Publishers Limited, part of Springer Nature
Place of publication:[London]
Document Type:Article
Year of Completion:2018
Date of first Publication:2018/10/23
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2018/11/13
Tag:Biophysical chemistry; Protein folding
Issue:1, Art. 15662
Page Number:10
First Page:1
Last Page:10
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Institutes:Physik / Physik
Biochemie, Chemie und Pharmazie / Biochemie und Chemie
Exzellenzcluster / Exzellenzcluster Makromolekulare Komplexe
Wissenschaftliche Zentren und koordinierte Programme / Sonderforschungsbereiche / Forschungskollegs
Wissenschaftliche Zentren und koordinierte Programme / Zentrum für Biomolekulare Magnetische Resonanz (BMRZ)
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften
5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie
Licence (German):License LogoCreative Commons - Namensnennung 4.0