title: A widespread bacterial type VI secretion effector superfamily identified using a heuristic approach.
abstract: Sophisticated mechanisms are employed to facilitate information exchange between interfacing bacteria. A type VI secretion system (T6SS) of Pseudomonas aeruginosa was shown to deliver cell wall-targeting effectors to neighboring cells. However, the generality of bacteriolytic effectors and, moreover, of antibacterial T6S remained unknown. Using parameters derived from experimentally validated bacterial T6SS effectors we identified a phylogenetically disperse superfamily of T6SS-associated peptidoglycan-degrading effectors. The effectors separate into four families composed of peptidoglycan amidase enzymes of differing specificities. Effectors strictly co-occur with cognate immunity proteins, indicating that self-intoxication is a general property of antibacterial T6SSs and effector delivery by the system exerts a strong selective pressure in nature. The presence of antibacterial effectors in a plethora of organisms, including many that inhabit or infect polymicrobial niches in the human body, suggests that the system could mediate interbacterial interactions of both environmental and clinical significance.
authors.affiliation: Department of Microbiology, University of Washington, Seattle, WA 98195, USA.
authors.forename: Alistair B
authors.initials: AB
authors.lastname: Russell
authors.forename: Pragya
authors.initials: P
authors.lastname: Singh
authors.forename: Mitchell
authors.initials: M
authors.lastname: Brittnacher
authors.forename: Nhat Khai
authors.initials: NK
authors.lastname: Bui
authors.forename: Rachel D
authors.initials: RD
authors.lastname: Hood
authors.forename: Mike A
authors.initials: MA
authors.lastname: Carl
authors.forename: Danielle M
authors.initials: DM
authors.lastname: Agnello
authors.forename: Sandra
authors.initials: S
authors.lastname: Schwarz
authors.forename: David R
authors.initials: DR
authors.lastname: Goodlett
authors.forename: Waldemar
authors.initials: W
authors.lastname: Vollmer
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Mougous
mesh_terms: D000581:Amidohydrolases / Q000235:genetics* / Q000378:metabolism; D000898:Antibiosis; D001419:Bacteria / Q000235:genetics* / Q000378:metabolism; D018407:Bacterial Physiological Phenomena; D058947:Bacterial Secretion Systems / Q000235:genetics*; D010457:Peptidoglycan / Q000378:metabolism
chemical_list: D058947:Bacterial Secretion Systems; D010457:Peptidoglycan; D000581:Amidohydrolases; C019665:amidase