TY  - JOUR
A1  - Dastvan, Reza
A1  - Brouwer, Eva-Maria
A1  - Schütz, Denise
A1  - Mirus, Oliver
A1  - Schleiff, Enrico
A1  - Prisner, Thomas F.
T1  - Relative orientation of POTRA domains from cyanobacterial Omp85 studied by pulsed EPR spectroscopy
T2  - Biophysical journal
N2  - Many proteins of the outer membrane of Gram-negative bacteria and of the outer envelope of the endosymbiotically derived organelles mitochondria and plastids have a β-barrel fold. Their insertion is assisted by membrane proteins of the Omp85-TpsB superfamily. These proteins are composed of a C-terminal β-barrel and a different number of N-terminal POTRA domains, three in the case of cyanobacterial Omp85. Based on structural studies of Omp85 proteins, including the five POTRA-domain-containing BamA protein of Escherichia coli, it is predicted that anaP2 and anaP3 bear a fixed orientation, whereas anaP1 and anaP2 are connected via a flexible hinge. We challenged this proposal by investigating the conformational space of the N-terminal POTRA domains of Omp85 from the cyanobacterium Anabaena sp. PCC 7120 using pulsed electron-electron double resonance (PELDOR, or DEER) spectroscopy. The pronounced dipolar oscillations observed for most of the double spin-labeled positions indicate a rather rigid orientation of the POTRA domains in frozen liquid solution. Based on the PELDOR distance data, structure refinement of the POTRA domains was performed taking two different approaches: 1) treating the individual POTRA domains as rigid bodies; and 2) using an all-atom refinement of the structure. Both refinement approaches yielded ensembles of model structures that are more restricted compared to the conformational ensemble obtained by molecular dynamics simulations, with only a slightly different orientation of N-terminal POTRA domains anaP1 and anaP2 compared with the x-ray structure. The results are discussed in the context of the native environment of the POTRA domains in the periplasm.
Y1  - 2017
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/43684
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-436848
SN  - 1542-0086
SN  - 0006-3495
N1  - © 2016 Biophysical Society.
VL  - 110
IS  - 10
SP  - 2195
EP  - 2206
PB  - Cell Press
CY  - Cambridge, Mass.
ER  -