title: An interbacterial NAD(P)(+) glycohydrolase toxin requires elongation factor Tu for delivery to target cells.
abstract: Type VI secretion (T6S) influences the composition of microbial communities by catalyzing the delivery of toxins between adjacent bacterial cells. Here, we demonstrate that a T6S integral membrane toxin from Pseudomonas aeruginosa, Tse6, acts on target cells by degrading the universally essential dinucleotides NAD(+) and NADP(+). Structural analyses of Tse6 show that it resembles mono-ADP-ribosyltransferase proteins, such as diphtheria toxin, with the exception of a unique loop that both excludes proteinaceous ADP-ribose acceptors and contributes to hydrolysis. We find that entry of Tse6 into target cells requires its binding to an essential housekeeping protein, translation elongation factor Tu (EF-Tu). These proteins participate in a larger assembly that additionally directs toxin export and provides chaperone activity. Visualization of this complex by electron microscopy defines the architecture of a toxin-loaded T6S apparatus and provides mechanistic insight into intercellular membrane protein delivery between bacteria.
authors.affiliation: Department of Microbiology, University of Washington, Seattle, WA 98195, USA.
authors.forename: John C
authors.initials: JC
authors.lastname: Whitney
authors.affiliation: Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany.
authors.forename: Dennis
authors.initials: D
authors.lastname: Quentin
authors.affiliation: Department of Microbiology, University of Washington, Seattle, WA 98195, USA.
authors.forename: Shin
authors.initials: S
authors.lastname: Sawai
authors.affiliation: Department of Microbiology, University of Washington, Seattle, WA 98195, USA.
authors.forename: Michele
authors.initials: M
authors.lastname: LeRoux
authors.affiliation: Department of Microbiology, University of Washington, Seattle, WA 98195, USA.
authors.forename: Brittany N
authors.initials: BN
authors.lastname: Harding
authors.affiliation: Department of Microbiology, University of Washington, Seattle, WA 98195, USA.
authors.forename: Hannah E
authors.initials: HE
authors.lastname: Ledvina
authors.affiliation: Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD 21201, USA.
authors.forename: Bao Q
authors.initials: BQ
authors.lastname: Tran
authors.affiliation: Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
authors.forename: Howard
authors.initials: H
authors.lastname: Robinson
authors.affiliation: Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD 21201, USA.
authors.forename: Young Ah
authors.initials: YA
authors.lastname: Goo
authors.affiliation: Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD 21201, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Goodlett
authors.affiliation: Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Otto-Hahn-Strasse 11, 44227 Dortmund, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Raunser
authors.affiliation: Department of Microbiology, University of Washington, Seattle, WA 98195, USA; Howard Hughes Medical Institute, Seattle, WA 98195, USA. Electronic address: mougous@u.washington.edu.
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Mougous
mesh_terms: D036002:ADP Ribose Transferases / Q000378:metabolism; D001427:Bacterial Toxins / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D009243:NAD / Q000378:metabolism; D009244:NAD+ Nucleosidase / Q000737:chemistry / Q000378:metabolism*; D009249:NADP / Q000378:metabolism; D010444:Peptide Elongation Factor Tu / Q000737:chemistry / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011550:Pseudomonas aeruginosa / Q000201:enzymology / Q000378:metabolism*; D000069376:Type VI Secretion Systems / Q000737:chemistry* / Q000378:metabolism
chemical_list: D001427:Bacterial Toxins; D000069376:Type VI Secretion Systems; D009243:NAD; D009249:NADP; D036002:ADP Ribose Transferases; D009244:NAD+ Nucleosidase; D010444:Peptide Elongation Factor Tu