The soluble loop BC region guides, but not dictates, the assembly of the transmembrane cytochrome b6

  • Studying folding and assembly of naturally occurring α-helical transmembrane proteins can inspire the design of membrane proteins with defined functions. Thus far, most studies have focused on the role of membrane-integrated protein regions. However, to fully understand folding pathways and stabilization of α–helical membrane proteins, it is vital to also include the role of soluble loops. We have analyzed the impact of interhelical loops on folding, assembly and stability of the heme-containing four-helix bundle transmembrane protein cytochrome b6 that is involved in charge transfer across biomembranes. Cytochrome b6 consists of two transmembrane helical hairpins that sandwich two heme molecules. Our analyses strongly suggest that the loop connecting the helical hairpins is not crucial for positioning the two protein “halves” for proper folding and assembly of the holo-protein. Furthermore, proteolytic removal of any of the remaining two loops, which connect the two transmembrane helices of a hairpin structure, appears to also not crucially effect folding and assembly. Overall, the transmembrane four-helix bundle appears to be mainly stabilized via interhelical interactions in the transmembrane regions, while the soluble loop regions guide assembly and stabilize the holo-protein. The results of this study might steer future strategies aiming at designing heme-binding four-helix bundle structures, involved in transmembrane charge transfer reactions.
Metadaten
Author:Lydia Tome-Stangl, Cornelia Schätzel, Stefan TenzerORCiDGND, Frank BernhardORCiD, Dirk Schneider
URN:urn:nbn:de:hebis:30:3-450151
DOI:https://doi.org/10.1371/journal.pone.0189532
ISSN:1932-6203
Pubmed Id:https://pubmed.ncbi.nlm.nih.gov/29240839
Parent Title (English):PLoS one
Publisher:PLoS
Place of publication:Lawrence, Kan.
Contributor(s):Eric Cascales
Document Type:Article
Language:English
Year of Completion:2017
Date of first Publication:2017/12/14
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2017/12/19
Tag:Cofactors (biochemistry); Detergents; Heme; Membrane proteins; Proteases; Protein structure; Proteolysis; RNA stem-loop structure
Volume:12
Issue:(12): e0189532
Page Number:20
First Page:1
Last Page:20
Note:
Copyright: © 2017 Tome-Stangl et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
HeBIS-PPN:426119568
Institutes:Biochemie, Chemie und Pharmazie / Biochemie und Chemie
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie
Sammlungen:Universitätspublikationen
Licence (German):License LogoCreative Commons - Namensnennung 4.0