Rhs toxins

In their large N-terminal region, Rhs toxins comprise RHS/YD repeats in various number ([http://pfam.xfam.org/family/PF05593 PF05593]) (RHS meaning Rearrangement Hot Spot) {{cite journal | vauthors = Hill CW, Sandt CH, Vlazny DA | title = Rhs elements of Escherichia coli: a family of genetic composites each encoding a large mosaic protein | journal = Molecular Microbiology | volume = 12 | issue = 6 | pages = 865–71 | date = June 1994 | pmid = 7934896 | doi = 10.1111/j.1365-2958.1994.tb01074.x | doi-access = free }} and another "RHS-repeats associated core" domain ([http://pfam.xfam.org/family/PF03527 PF03527]). In contrast, their C-terminal regions are shorter and harbor highly variable C-terminal domains including many domains with a predicted nuclease activity.

These toxins encompass Rhs toxins of insect pathogens with an activity against insects.{{cite journal | vauthors = Busby JN, Panjikar S, Landsberg MJ, Hurst MR, Lott JS | title = The BC component of ABC toxins is an RHS-repeat-containing protein encapsulation device | journal = Nature | volume = 501 | issue = 7468 | pages = 547–50 | date = September 2013 | pmid = 23913273 | doi = 10.1038/nature12465 | s2cid = 4448084 | url = http://espace.library.uq.edu.au/view/UQ:313861/Busby_Nature_2014_postrefereed.pdf }} This group also include Rhs toxins with an activity against human phagocytic cells that contribute to pathogenesis of Pseudomonas aeruginosa.{{cite journal | vauthors = Kung VL, Khare S, Stehlik C, Bacon EM, Hughes AJ, Hauser AR | title = An rhs gene of Pseudomonas aeruginosa encodes a virulence protein that activates the inflammasome | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 109 | issue = 4 | pages = 1275–80 | date = January 2012 | pmid = 22232685 | pmc = 3268321 | doi = 10.1073/pnas.1109285109 | doi-access = free }}

A role in inter-bacterial competition has been demonstrated for the plant pathogen Dickeya dadantii and for the human pathogen Escherichia coli.{{cite journal | vauthors = Koskiniemi S, Lamoureux JG, Nikolakakis KC, t'Kint de Roodenbeke C, Kaplan MD, Low DA, Hayes CS | title = Rhs proteins from diverse bacteria mediate intercellular competition | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 110 | issue = 17 | pages = 7032–7 | date = April 2013 | pmid = 23572593 | pmc = 3637788 | doi = 10.1073/pnas.1300627110 | doi-access = free }}{{cite journal | vauthors = Ma J, Sun M, Dong W, Pan Z, Lu C, Yao H | title = PAAR-Rhs proteins harbor various C-terminal toxins to diversify the antibacterial pathways of type VI secretion systems | journal = Environmental Microbiology | volume = 19 | issue = 1 | pages = 345–360 | date = January 2017 | pmid = 27871130 | doi = 10.1111/1462-2920.13621 | s2cid = 22339707 }}

When a polymorphic toxin with anti-bacterial activity is produced by a bacterial strain, this strain is protected by a specific immunity protein encoded by a gene immediately downstream of the toxin gene.

Some Rhs toxins such as the previously mentioned system in Dickeya dadantii appear to be dependent on the type VI secretion system for delivery into neighbouring cells. PAAR domain toxins such as Rhs appear to form the sharp tip of the type VI secretion system being attached to the VgrG of the secretion apparatus.{{cite journal | vauthors = Shneider MM, Buth SA, Ho BT, Basler M, Mekalanos JJ, Leiman PG | title = PAAR-repeat proteins sharpen and diversify the type VI secretion system spike | language = En | journal = Nature | volume = 500 | issue = 7462 | pages = 350–353 | date = August 2013 | pmid = 23925114 | pmc = 3792578 | doi = 10.1038/nature12453 | url = https://dash.harvard.edu/bitstream/handle/1/11879901/3792578.pdf?sequence=1 }} The C-terminal toxins of Rhs may vary to diversify the antimicrobial activity of the type VI secretion system.

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• [https://www.ebi.ac.uk/interpro/entry/IPR001826?q=rhs Rhs proteins in the InterPro database]

Category:Bacterial toxins