4EQA

Crystal structure of PA1844 in complex with PA1845 from Pseudomonas aeruginosa PAO1

Summary for 4EQA

• Entry DOI: 10.2210/pdb4eqa/pdb
• Related: 4EQ8
• Descriptor: Putative uncharacterized protein (3 entities in total)
• Functional Keywords: type vi secretion, t6s, antitoxin-toxin complex, unknown function
• Biological source: Pseudomonas aeruginosa; More
• Total number of polymer chains: 4
• Total formula weight: 64992.85

Authors

Shang, G.,Li, N.,Zhang, J.,Lu, D.,Yu, Q.,Zhao, Y.,Liu, X.,Xu, S.,Gu, L. (deposition date: 2012-04-18, release date: 2012-09-12, Last modification date: 2024-10-30)

Primary citation

Shang, G.,Liu, X.,Lu, D.,Zhang, J.,Li, N.,Zhu, C.,Liu, S.,Yu, Q.,Zhao, Y.,Zhang, H.,Hu, J.,Cang, H.,Xu, S.,Gu, L.
Structural insight into how Pseudomonas aeruginosa peptidoglycanhydrolase Tse1 and its immunity protein Tsi1 function.
Biochem.J., 448:201-211, 2012

PubMed Abstract: Tse1 (Tse is type VI secretion exported), an effector protein produced by Pseudomonas aeruginosa, is an amidase that hydrolyses the γ-D-glutamyl-DAP (γ-D-glutamyl-L-meso-diaminopimelic acid) linkage of the peptide bridge of peptidoglycan. P. aeruginosa injects Tse1 into the periplasm of recipient cells, degrading their peptidoglycan, thereby helping itself to compete with other bacteria. Meanwhile, to protect itself from injury by Tse1, P. aeruginosa expresses the cognate immunity protein Tsi1 (Tsi is type VI secretion immunity) in its own periplasm to inactivate Tse1. In the present paper, we report the crystal structures of Tse1 and the Tse1-(6-148)-Tsi1-(20-end) complex at 1.4 Å and 1.6 Å (1 Å=0.1 nm) resolutions respectively. The Tse1 structure adopts a classical papain-like α+β fold. A cysteine-histidine catalytic diad is identified in the reaction centre of Tse1 by structural comparison and mutagenesis studies. Tsi1 binds Tse1 tightly. The HI loop (middle finger tip) from Tsi1 inserts into the large pocket of the Y-shaped groove on the surface of Tse1, and CD, EF, JK and LM loops (thumb, index finger, ring finger and little finger tips) interact with Tse1, thus blocking the binding of enzyme to peptidoglycan. The catalytic and inhibition mechanisms provide new insights into how P. aeruginosa competes with others and protects itself.

PubMed: 22931054
DOI: 10.1042/BJ20120668

Experimental method

X-RAY DIFFRACTION (1.6 Å)