Crystal structure of the type VI immunity protein Tdi1 (Atu4351) from Agrobacterium tumefaciens. Issue 3 (7th March 2019)

• Record Type: Journal Article
• Authors: Shi, Lingling; Gao, Zengqiang; Zhang, Tianyi; Zhang, Heng; Dong, Yuhui
• Is Part Of: Acta crystallographica. Volume 75:Issue 3(2019:Mar.)
• Page Start: 153
• Page End: 158
• Publication Date: 2019-03-07
• Subjects: type VI secretion system -- effector–immunity pair -- Tdi1 -- GAD‐like domain -- DUF1851 domain -- bacterial nanomachines; Crystallography -- Periodicals; Crystals -- Periodicals; 548
• DOI: 10.1107/S2053230X19000815
• Languages: English
• ISSNs: 2053-230X

Abstract

Abstract : The crystal structure of Tdi1 (Atu4351) from Agrobacterium tumefaciens is composed of a GAD‐like domain and an inserted DUF1851 domain. Abstract : The type VI secretion system (T6SS) is a novel multiprotein needle‐like apparatus that is distributed widely in Gram‐negative bacteria. Bacteria harboring T6SSs inject various effectors into both eukaryotic and prokaryotic cells for interspecies competition or virulence‐related processes. The toxicities of the effectors can be neutralized by their cognate immunity proteins. Tde1 (Atu4350)–Tdi1 (Atu4351) has recently been characterized as a T6SS effector–immunity pair in the soil bacterium Agrobacterium tumefaciens and the neutralization mechanism remains unknown. Here, the crystal structure of the immunity protein Tdi1 was determined at 2.40 Å resolution by the single‐wavelength anomalous dispersion method. Structural analysis suggested that it is composed of a GAD‐like domain and an inserted DUF1851 domain, and both domains show low structural similarities to known structures. There is a positive groove mainly located in the GAD‐like domain that may be associated with nucleotide binding. The structure provides a basis for further study of the positive groove as a potential active site.