PDBsum entry 5d6h

Chaperone/protein transport

PDB id: 5d6h

Contents

Protein chains

223 a.a.

98 a.a.

Waters ×158

PDB id:

5d6h

Name:

Chaperone/protein transport

Title:

Crystal structure of csuc-csua/b chaperone-major subunit pre-assembly complex from csu biofilm-mediating pili of acinetobacter baumannii

Structure:

Csuc. Chain: a. Fragment: unp residues 35-277. Engineered: yes. Csua/b. Chain: b. Fragment: unp residues 38-180. Engineered: yes

Source:

Acinetobacter baumannii. Organism_taxid: 470. Gene: csuc. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693. Expression_system_variant: ai. Gene: csua/b.

Resolution:

2.40Å R-factor: 0.224 R-free: 0.266

Authors:

N.A.Pakharukova,M.Tuitilla,S.Paavilainen,A.Zavialov

Key ref:

N.Pakharukova et al. (2015). Structural Insight into Archaic and Alternative Chaperone-Usher Pathways Reveals a Novel Mechanism of Pilus Biogenesis. Plos Pathog, 11, e1005269. PubMed id: 26587649 DOI: 10.1371/journal.ppat.1005269

Date:

12-Aug-15 Release date: 04-Nov-15

Protein chain

Q6XBY4  (Q6XBY4_ACIBA) -  CsuC from Acinetobacter baumannii

Seq: 277 a.a.

Struc: 223 a.a.

Protein chain

Q6XBY7  (Q6XBY7_ACIBA) -  CsuA/B from Acinetobacter baumannii

Seq: 180 a.a.

Struc: 98 a.a.*

* PDB and UniProt seqs differ at 3 residue positions (black crosses)

DOI no: 10.1371/journal.ppat.1005269

Plos Pathog 11:e1005269 (2015)

PubMed id: 26587649

Structural Insight into Archaic and Alternative Chaperone-Usher Pathways Reveals a Novel Mechanism of Pilus Biogenesis.

N.Pakharukova, J.A.Garnett, M.Tuittila, S.Paavilainen, M.Diallo, Y.Xu, S.J.Matthews, A.V.Zavialov.

ABSTRACT

Gram-negative pathogens express fibrous adhesive organelles that mediate targeting to sites of infection. The major class of these organelles is assembled via the classical, alternative and archaic chaperone-usher pathways. Although non-classical systems share a wider phylogenetic distribution and are associated with a range of diseases, little is known about their assembly mechanisms. Here we report atomic-resolution insight into the structure and biogenesis of Acinetobacter baumannii Csu and Escherichia coli ECP biofilm-mediating pili. We show that the two non-classical systems are structurally related, but their assembly mechanism is strikingly different from the classical assembly pathway. Non-classical chaperones, unlike their classical counterparts, maintain subunits in a substantially disordered conformational state, akin to a molten globule. This is achieved by a unique binding mechanism involving the register-shifted donor strand complementation and a different subunit carboxylate anchor. The subunit lacks the classical pre-folded initiation site for donor strand exchange, suggesting that recognition of its exposed hydrophobic core starts the assembly process and provides fresh inspiration for the design of inhibitors targeting chaperone-usher systems.