TY  - JOUR
A1  - D'Imprima, Edoardo
A1  - Salzer, Ralf
A1  - Bhaskara, Ramachandra M.
A1  - Sánchez, Ricardo
A1  - Rose, Ilona
A1  - Kirchner, Lennart
A1  - Hummer, Gerhard
A1  - Kühlbrandt, Werner
A1  - Vonck, Janet
A1  - Averhoff, Beate
T1  - Cryo-EM structure of the bifunctional secretin complex of Thermus thermophilus
T2  - eLife
N2  - Secretins form multimeric channels across the outer membrane of Gram-negative bacteria that mediate the import or export of substrates and/or extrusion of type IV pili. The secretin complex of Thermus thermophilus is an oligomer of the 757-residue PilQ protein, essential for DNA uptake and pilus extrusion. Here, we present the cryo-EM structure of this bifunctional complex at a resolution of ~7 Å using a new reconstruction protocol. Thirteen protomers form a large periplasmic domain of six stacked rings and a secretin domain in the outer membrane. A homology model of the PilQ protein was fitted into the cryo-EM map. A crown-like structure outside the outer membrane capping the secretin was found not to be part of PilQ. Mutations in the secretin domain disrupted the crown and abolished DNA uptake, suggesting a central role of the crown in natural transformation.
KW  - Research article
KW  - Biophysics and structural biology
KW  - Thermus thermophilus
KW  - Secretin
KW  - Natural transformation
KW  - Pilus
KW  - Cryo-electron microscopy
Y1  - 2017
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/45575
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-455752
SN  - 2050-084X
N1  - Copyright D’Imprima et al. This article is distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use and redistribution provided that the original author and source are credited.
VL  - 6
IS  - e30483
SP  - 1
EP  - 23
PB  - eLife Sciences Publications
CY  - Cambridge
ER  -