TY  - JOUR
A1  - Tome-Stangl, Lydia
A1  - Schätzel, Cornelia
A1  - Tenzer, Stefan
A1  - Bernhard, Frank
A1  - Schneider, Dirk
T1  - The soluble loop BC region guides, but not dictates, the assembly of the transmembrane cytochrome b6
T2  - PLoS one
N2  - 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.
KW  - Heme
KW  - Proteases
KW  - Proteolysis
KW  - Cofactors (biochemistry)
KW  - Membrane proteins
KW  - Detergents
KW  - Protein structure
KW  - RNA stem-loop structure
Y1  - 2017
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/45015
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-450151
SN  - 1932-6203
N1  - 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.
VL  - 12
IS  - (12): e0189532
SP  - 1
EP  - 20
PB  - PLoS
CY  - Lawrence, Kan.
ER  -