| 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
The target range of a bacterial secretion system can be defined by effector substrate specificity or by the efficacy of effector delivery. Here, we report the crystal structure of Tse1, a type VI secretion (T6S) bacteriolytic amidase effector from Pseudomonas aeruginosa. Consistent with its role as a toxin, Tse1 has a more accessible active site than related housekeeping enzymes. The activity of Tse1 against isolated peptidoglycan shows its capacity to act broadly against Gram-negative bacteria and even certain Gram-positive species. Studies with intact cells indicate that Gram-positive bacteria can remain vulnerable to Tse1 despite cell wall modifications. However, interbacterial competition studies demonstrate that Tse1-dependent lysis is restricted to Gram-negative targets. We propose that the previously observed specificity for T6S against Gram-negative bacteria is a consequence of high local effector concentration achieved by T6S-dependent targeting to its site of action rather than inherent effector substrate specificity.
Structure of a peptidoglycan amidase effector targeted to Gram-negative bacteria by the type VI secretion system.,Chou S, Bui NK, Russell AB, Lexa KW, Gardiner TE, LeRoux M, Vollmer W, Mougous JD Cell Rep. 2012 Jun 28;1(6):656-64. Epub 2012 May 31. PMID:22813741[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
- ↑ 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
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