Peptide translocation by the lysosomal ABC transporter TAPL is regulated by coupling efficiency and activation energy

  • The lysosomal polypeptide transporter TAPL belongs to the superfamily of ATP-binding cassette transporters. TAPL forms a homodimeric transport complex, which translocates oligo- and polypeptides into the lumen of lysosomes driven by ATP hydrolysis. Although the structure and the function of ABC transporters were intensively studied in the past, details about the single steps of the transport cycle are still elusive. Therefore, we analyzed the coupling of peptide binding, transport and ATP hydrolysis for different substrate sizes. Although longer and shorter peptides bind with the same affinity and are transported with identical Km values, they differ significantly in their transport rates. This difference can be attributed to a higher activation energy for the longer peptide. TAPL shows a basal ATPase activity, which is inhibited in the presence of longer peptides. Uncoupling between ATP hydrolysis and peptide transport increases with peptide length. Remarkably, also the type of nucleotide determines the uncoupling. While GTP is hydrolyzed as good as ATP, peptide transport is significantly reduced. In conclusion, TAPL does not differentiate between transport substrates in the binding process but during the following steps in the transport cycle, whereas, on the other hand, not only the coupling efficiency but also the activation energy varies depending on the size of peptide substrate.

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Author:Christoph Bock, Tina Zollmann, Katharina-Astrid Lindt, Robert TampéORCiDGND, Rupert Abele
URN:urn:nbn:de:hebis:30:3-507502
DOI:https://doi.org/10.1038/s41598-019-48343-6
ISSN:2045-2322
Pubmed Id:https://pubmed.ncbi.nlm.nih.gov/31417173
Parent Title (English):Scientific reports
Publisher:Macmillan Publishers Limited, part of Springer Nature
Place of publication:[London]
Document Type:Article
Language:English
Year of Completion:2019
Date of first Publication:2019/08/15
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2019/08/19
Tag:Enzyme mechanisms; Membrane proteins
Volume:9
Issue:1, Art. 11884
Page Number:12
First Page:1
Last Page:12
Note:
Open Access: This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
HeBIS-PPN:453741169
Institutes:Biochemie, Chemie und Pharmazie / Biochemie und Chemie
Wissenschaftliche Zentren und koordinierte Programme / Sonderforschungsbereiche / Forschungskollegs
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie
Sammlungen:Universitätspublikationen
Licence (German):License LogoCreative Commons - Namensnennung 4.0