| Structural highlights
Function
TSE1_PSEAE Toxin secreted by the H1 type VI (H1-T6SS) secretion system into the periplasm of recipient cells. Degrades peptidoglycan via amidase activity thereby helping itself to compete with other bacteria (PubMed:21776080, PubMed:22700987, PubMed:22813741, PubMed:22931054). To protect itself, the bacterium synthesizes immunity protein Tsi1 that specifically interacts with and inactivates cognate toxin (PubMed:21776080, PubMed:22700987, PubMed:22931054).[1] [2] [3] [4]
Publication Abstract from PubMed
Tse1, an effector protein produced by Pseudomonas aeruginosa, is an amidase hydrolyzing gamma-D-glutamyl-L-meso-diaminopimelic acid (gamma-D-glutamyl-DAP) 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 in its own periplasm to inactivate Tse1. In the present study, we report the crystal structures of Tse1 and Tse1 (6-148)-Tsi1 (20-end) complex at 1.4 A and 1.6 A resolutions, respectively. The Tse1 structure adopts a classical papain-like alpha+beta fold. A Cys-His 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 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 give new insights into how P. aeruginosa competes with others and protects itself..
Structural insight into functioning of Pseudomonas aeruginosa peptidoglycan-hydolase Tse1 and its immunity protein Tsi1.,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 Biochem J. 2012 Aug 29. PMID:22931054[5]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Russell AB, Hood RD, Bui NK, LeRoux M, Vollmer W, Mougous JD. Type VI secretion delivers bacteriolytic effectors to target cells. Nature. 2011 Jul 20;475(7356):343-7. doi: 10.1038/nature10244. PMID:21776080 doi:http://dx.doi.org/10.1038/nature10244
- ↑ Ding J, Wang W, Feng H, Zhang Y, Wang DC. Structural insights into the Pseudomonas aeruginosa type VI virulence effector Tse1 bacteriolysis and self-protection mechanisms. J Biol Chem. 2012 Jun 14. PMID:22700987 doi:10.1074/jbc.M112.368043
- ↑ Chou S, Bui NK, Russell AB, Lexa KW, Gardiner TE, LeRoux M, Vollmer W, Mougous JD. Structure of a peptidoglycan amidase effector targeted to Gram-negative bacteria by the type VI secretion system. Cell Rep. 2012 Jun 28;1(6):656-64. Epub 2012 May 31. PMID:22813741 doi:http://dx.doi.org/10.1016/j.celrep.2012.05.016
- ↑ 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 functioning of Pseudomonas aeruginosa peptidoglycan-hydolase Tse1 and its immunity protein Tsi1. Biochem J. 2012 Aug 29. PMID:22931054 doi:10.1042/BJ20120668
- ↑ 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 functioning of Pseudomonas aeruginosa peptidoglycan-hydolase Tse1 and its immunity protein Tsi1. Biochem J. 2012 Aug 29. PMID:22931054 doi:10.1042/BJ20120668
|
