Article

Crystal structure of type VI effector Tse1 from Pseudomonas aeruginosa.

State Key Laboratory of Protein and Plant Gene Research, and Biodynamic Optical Imaging Center (BIOPIC), School of Life Sciences, Peking University, No. 5 Yiheyuan Road, Beijing 100871, China; Shenzhen Graduate School of Peking University, Shenzhen 518055, China; Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China.
FEBS letters (Impact Factor: 3.54). 06/2012; 586(19):3193-9. DOI: 10.1016/j.febslet.2012.06.036
Source: PubMed

ABSTRACT The type VI secretion systems (T6SS) have emerging roles in interspecies competition. In order to have an advantage in defense against other organisms, this system in Pseudomonas aeruginosa delivers a peptidoglycan amidase (Tse1) to the periplasmic space of a competitor. An immune protein (Tsi1) is also produced by the bacterium to protect itself from damage caused by Tse1. Tsi1 directly interacts with Tse1. We report that the crystal structure of Tse1 displays a common CHAP protein fold. Strikingly, our structures showed that the third residue in the catalytic triad may be novel as this residue type has not been observed previously.

0 Bookmarks
 · 
112 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: The type VI secretion system (T6SS) mediates interactions between a broad range of Gram-negative bacterial species. Recent studies have led to a substantial increase in the number of characterized T6SS effector proteins and a more complete and nuanced view of the adaptive importance of the system. Although the T6SS is most often implicated in antagonism, in this Review, we consider the case for its involvement in both antagonistic and non-antagonistic behaviours. Clarifying the roles that type VI secretion has in microbial communities will contribute to broader efforts to understand the importance of microbial interactions in maintaining human and environmental health, and will inform efforts to manipulate these interactions for therapeutic or environmental benefit.
    Nature Reviews Microbiology 01/2014; · 22.49 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The bacterial type VI secretion system (T6SS) is used by donor cells to inject toxic effectors into receptor cells. The donor cells produce the corresponding immunity proteins to protect themselves against the effector proteins, thereby preventing their self-intoxication. Recently, the C-terminal domain of VgrG3 was identified as a T6SS effector. Information on the molecular mechanism of VgrG3 and its immunity protein TsaB has been lacking. Here, we determined the crystal structures of native TsaB and the VgrG3C-TsaB complex. VgrG3C adopts a canonical phage-T4-lysozyme-like fold. TsaB interacts with VgrG3C through molecular mimicry, and inserts into the VgrG3C pocket.
    FEBS letters 04/2014; · 3.54 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Bacteria do not live anchoretic; rather they are constantly in touch with their eukaryotic hosts and with other bacteria sharing their habitat. Therefore, bacteria have evolved sophisticated proteinaceous weapons. To harm other bacteria, they produce antibacterial effector proteins, which they either release into the environment or export via direct intercellular contact. Contact-dependent killing is mediated by two specialized secretion systems, the type V and VI secretion system, whereas contact-independent processes hijack other transport mechanisms. Regardless of the transport system, cells co-express immunity proteins to protect themselves from suicide and fratricide. In general, effector protein activities and secretion mechanisms differ between Gram-positive and Gram-negative bacteria and evidence is emerging that different effector/immunity systems act synergistically and thus extend the bacterial armory.
    Current opinion in microbiology 02/2014; 17C:1-10. · 7.87 Impact Factor