Authors:	Tome-Stangl, Lydia Schätzel, Cornelia Tenzer, Stefan Bernhard, Frank Schneider, Dirk
Title:	The soluble loop BC region guides, but not dictates, the assembly of the transmembrane cytochrome b6
Online publication date:	13-Jun-2022
Year of first publication:	2017
Language:	english
Abstract:	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.
DDC:	500 Naturwissenschaften 500 Natural sciences and mathematics
Institution:	Johannes Gutenberg-Universität Mainz
Department:	FB 04 Medizin FB 09 Chemie, Pharmazie u. Geowissensch.
Place:	Mainz
ROR:	https://ror.org/023b0x485
DOI:	http://doi.org/10.25358/openscience-7124
Version:	Published version
Publication type:	Zeitschriftenaufsatz
License:	CC BY
Information on rights of use:	https://creativecommons.org/licenses/by/4.0/
Journal:	PLOS ONE 12 12
Pages or article number:	e0189532
Publisher:	PLOS
Publisher place:	San Francisco, California, US
Issue date:	2017
ISSN:	1932-6203
Publisher URL:	http://dx.doi.org/10.1371/journal.pone.0189532
Publisher DOI:	10.1371/journal.pone.0189532
Appears in collections:	DFG-OA-Publizieren (2012 - 2017)