4uqx
From Proteopedia
Coevolution of the ATPase ClpV, the TssB-TssC Sheath and the Accessory HsiE Protein Distinguishes Two Type VI Secretion Classes
Structural highlights
FunctionTAGJ_PSEAE Component of the H1 type VI (H1-T6SS) secretion system that plays a role in the release of toxins targeting both eukaryotic and prokaryotic species. Forms a stable complex with TssB1. This complex, although not crucial for the H1-T6SS function, may fine-tune the assembly of the system (PubMed:22906320). Plays a role in the interaction between ClpV1 and the TssC1/TssB1 sheath (PubMed:25305017).[1] [2] Publication Abstract from PubMedThe type VI secretion system (T6SS) is a bacterial nanomachine for the transport of effector molecules into prokaryotic and eukaryotic cells. It involves the assembly of a tubular structure composed of TssB and TssC that is similar to the tail sheath of bacteriophages. The sheath contracts to provide the energy needed for effector delivery. The AAA+ ATPase ClpV disassembles the contracted sheath, which resets the systems for reassembly of an extended sheath that is ready to fire again. This mechanism is crucial for T6SS function. In Vibrio cholerae, ClpV binds the N terminus of TssC within a hydrophobic groove. In this study, we resolved the crystal structure of the N-terminal domain of Pseudomonas aeruginosa ClpV1 and observed structural alterations in the hydrophobic groove. The modification in the ClpV1 groove is matched by a change in the N terminus of TssC, suggesting the existence of distinct T6SS classes. An accessory T6SS component, TagJ/HsiE, exists predominantly in one of the classes. Using bacterial two-hybrid approaches, we showed that the P. aeruginosa homolog HsiE1 interacts strongly with ClpV1. We then resolved the crystal structure of HsiE1 in complex with the N terminus of HsiB1, a TssB homolog and component of the contractile sheath. Phylogenetic analysis confirmed that these differences distinguish T6SS classes that resulted from a functional co-evolution between TssB, TssC, TagJ/HsiE and ClpV. The interaction of TagJ/HsiE with the sheath as well as with ClpV suggests an alternative mode of disassembly in which HsiE recruits the ATPase to the sheath. Coevolution of the ATPase ClpV, the Sheath Proteins TssB and TssC and the Accessory Protein TagJ/HsiE1 Distinguishes Type VI Secretion Classes.,Forster A, Planamente S, Manoli E, Lossi NS, Freemont PS, Filloux A J Biol Chem. 2014 Oct 10. pii: jbc.M114.600510. PMID:25305017[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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