6FQA

Crystal structure of the CsuC-CsuA/B chaperone-subunit preassembly complex of the archaic chaperone-usher Csu pili of Acinetobacter baumannii

Summary for 6FQA

• Entry DOI: 10.2210/pdb6fqa/pdb
• Related: 5D6H 6FM5 6FQ0
• Descriptor: CsuC, CsuA/B,CsuA/B (2 entities in total)
• Functional Keywords: ig-like fold, beta sandwich, donor-strand complementation, cell adhesion
• Biological source: Acinetobacter baumannii; More
• Total number of polymer chains: 4
• Total formula weight: 85870.16

Authors

Parilova, O.,Pakharukova, N.A.,Malmi, H.,Tuitilla, M.,Paavilainen, S.,Zavialov, A.V. (deposition date: 2018-02-13, release date: 2018-09-26, Last modification date: 2024-11-13)

Primary citation

Pakharukova, N.,McKenna, S.,Tuittila, M.,Paavilainen, S.,Malmi, H.,Xu, Y.,Parilova, O.,Matthews, S.,Zavialov, A.V.
Archaic and alternative chaperones preserve pilin folding energy by providing incomplete structural information.
J. Biol. Chem., 293:17070-17080, 2018

PubMed Abstract: Adhesive pili are external component of fibrous adhesive organelles and help bacteria attach to biotic or abiotic surfaces. The biogenesis of adhesive pili via the chaperone-usher pathway (CUP) is independent of external energy sources. In the classical CUP, chaperones transport assembly-competent pilins in a folded but expanded conformation. During donor-strand exchange, pilins subsequently collapse, producing a tightly packed hydrophobic core and releasing the necessary free energy to drive fiber formation. Here, we show that pilus biogenesis in non-classical, archaic, and alternative CUPs uses a different source of conformational energy. High-resolution structures of the archaic Csu-pili system from revealed that non-classical chaperones employ a short donor strand motif that is insufficient to fully complement the pilin fold. This results in chaperone-bound pilins being trapped in a substantially unfolded intermediate. The exchange of this short motif with the longer donor strand from adjacent pilin provides the full steric information essential for folding, and thereby induces a large unfolded-to-folded conformational transition to drive assembly. Our findings may inform the development of anti-adhesion drugs (pilicides) to combat bacterial infections.

PubMed: 30228191
DOI: 10.1074/jbc.RA118.004170

Experimental method

X-RAY DIFFRACTION (2.85 Å)