PDBsum entry 5cul

Cell invasion

PDB id: 5cul

Contents

Protein chains

28 a.a.

79 a.a.

Waters ×6

PDB id:

5cul

Name:

Cell invasion

Title:

Crystal structure of the pscu c-terminal domain

Structure:

Translocation protein in type iii secretion. Chain: a, b. Engineered: yes

Source:

Pseudomonas aeruginosa (strain atcc 15692 / pao1 / 1c / prs 101 / lmg 12228). Organism_taxid: 208964. Strain: atcc 15692 / pao1 / 1c / prs 101 / lmg 12228. Gene: pscu, pa1690. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

2.90Å R-factor: 0.197 R-free: 0.225

Authors:

J.R.C.Bergeron,N.C.J.Strynadka

Key ref:

J.R.Bergeron et al. (2016). The Structure of a Type 3 Secretion System (T3SS) Ruler Protein Suggests a Molecular Mechanism for Needle Length Sensing. J Biol Chem, 291, 1676-1691. PubMed id: 26589798 DOI: 10.1074/jbc.M115.684423

Date:

24-Jul-15 Release date: 02-Dec-15

Protein chain

Q9I337  (Q9I337_PSEAE) -  Translocation protein in type III secretion from Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 / JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1)

Seq: 349 a.a.

Struc: 28 a.a.

Protein chain

Q9I337  (Q9I337_PSEAE) -  Translocation protein in type III secretion from Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 / JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1)

Seq: 349 a.a.

Struc: 79 a.a.

DOI no: 10.1074/jbc.M115.684423

J Biol Chem 291:1676-1691 (2016)

PubMed id: 26589798

The Structure of a Type 3 Secretion System (T3SS) Ruler Protein Suggests a Molecular Mechanism for Needle Length Sensing.

J.R.Bergeron, L.Fernández, G.A.Wasney, M.Vuckovic, F.Reffuveille, R.E.Hancock, N.C.Strynadka.

ABSTRACT

The type 3 secretion system (T3SS) and the bacterial flagellum are related pathogenicity-associated appendages found at the surface of many disease-causing bacteria. These appendages consist of long tubular structures that protrude away from the bacterial surface to interact with the host cell and/or promote motility. A proposed "ruler" protein tightly regulates the length of both the T3SS and the flagellum, but the molecular basis for this length control has remained poorly characterized and controversial. Using the Pseudomonas aeruginosa T3SS as a model system, we report the first structure of a T3SS ruler protein, revealing a "ball-and-chain" architecture, with a globular C-terminal domain (the ball) preceded by a long intrinsically disordered N-terminal polypeptide chain. The dimensions and stability of the globular domain do not support its potential passage through the inner lumen of the T3SS needle. We further demonstrate that a conserved motif at the N terminus of the ruler protein interacts with the T3SS autoprotease in the cytosolic side. Collectively, these data suggest a potential mechanism for needle length sensing by ruler proteins, whereby upon T3SS needle assembly, the ruler protein's N-terminal end is anchored on the cytosolic side, with the globular domain located on the extracellular end of the growing needle. Sequence analysis of T3SS and flagellar ruler proteins shows that this mechanism is probably conserved across systems.