4UV2

Structure of the curli transport lipoprotein CsgG in a non-lipidated, pre-pore conformation

Summary for 4UV2

• Entry DOI: 10.2210/pdb4uv2/pdb
• Related: 4UV3
• Descriptor: CURLI PRODUCTION TRANSPORT COMPONENT CSGG (1 entity in total)
• Functional Keywords: transport protein, outer membrane protein
• Biological source: ESCHERICHIA COLI STR. K-12 SUBSTR. MC4100
• Cellular location: Cell membrane ; Lipid-anchor : P0AEA2
• Total number of polymer chains: 16
• Total formula weight: 466803.09

Authors

Goyal, P.,Krasteva, P.V.,Gerven, N.V.,Gubellini, F.,Broeck, I.V.D.,Troupiotis-Tsailaki, A.,Jonckheere, W.,Pehau-Arnaudet, G.,Pinkner, J.S.,Chapman, M.R.,Hultgren, S.J.,Howorka, S.,Fronzes, R.,Remaut, H. (deposition date: 2014-08-04, release date: 2014-09-24, Last modification date: 2014-12-17)

Primary citation

Goyal, P.,Krasteva, P.V.,Van Gerven, N.,Gubellini, F.,Van Den Broeck, I.,Troupiotis-Tsailaki, A.,Jonckheere, W.,Pehau-Arnaudet, G.,Pinkner, J.S.,Chapman, M.R.,Hultgren, S.J.,Howorka, S.,Fronzes, R.,Remaut, H.
Structural and Mechanistic Insights Into the Bacterial Amyloid Secretion Channel Csgg.
Nature, 516:250-, 2014

PubMed Abstract: Curli are functional amyloid fibres that constitute the major protein component of the extracellular matrix in pellicle biofilms formed by Bacteroidetes and Proteobacteria (predominantly of the α and γ classes). They provide a fitness advantage in pathogenic strains and induce a strong pro-inflammatory response during bacteraemia. Curli formation requires a dedicated protein secretion machinery comprising the outer membrane lipoprotein CsgG and two soluble accessory proteins, CsgE and CsgF. Here we report the X-ray structure of Escherichia coli CsgG in a non-lipidated, soluble form as well as in its native membrane-extracted conformation. CsgG forms an oligomeric transport complex composed of nine anticodon-binding-domain-like units that give rise to a 36-stranded β-barrel that traverses the bilayer and is connected to a cage-like vestibule in the periplasm. The transmembrane and periplasmic domains are separated by a 0.9-nm channel constriction composed of three stacked concentric phenylalanine, asparagine and tyrosine rings that may guide the extended polypeptide substrate through the secretion pore. The specificity factor CsgE forms a nonameric adaptor that binds and closes off the periplasmic face of the secretion channel, creating a 24,000 Å(3) pre-constriction chamber. Our structural, functional and electrophysiological analyses imply that CsgG is an ungated, non-selective protein secretion channel that is expected to employ a diffusion-based, entropy-driven transport mechanism.

PubMed: 25219853
DOI: 10.1038/NATURE13768

Experimental method

X-RAY DIFFRACTION (2.8 Å)