Structural characterization of the hypothetical protein Lpg2622, a new member of the C1 family peptidases from Legionella pneumophila
Gong, X., Zhao, X., Zhang, W., Wang, J., Chen, X., Hameed, M.F., Zhang, N., Ge, H.(2018) FEBS Lett 592: 2798-2810
- PubMed: 30071124 
- DOI: https://doi.org/10.1002/1873-3468.13210
- Primary Citation of Related Structures:  
6A0N, 6A0Q - PubMed Abstract: 
The Legionella pneumophila type II secretion system can promote bacterial growth under a wide variety of conditions and mediates the secretion of more than 25 proteins, including the uncharacterized effector Lpg2622. Here, we determined the crystal structures of apo-Lpg2622 and Lpg2622 in complex with the cysteine protease inhibitor E64. Structural analysis suggests that Lpg2622 belongs to the C1 family peptidases. Interestingly, unlike the other structurally resolved papain-like cysteine proteases, the propeptide of Lpg2622 forms a novel super-secondary structural fold (hairpin-turn-helix) and can be categorized into a new group. In addition, the N-terminal β-sheet of the Lpg2622 propeptide plays a regulatory role on enzymatic activity. This study enhances our understanding of the classification and regulatory mechanisms of the C1 family peptidases.
Organizational Affiliation: 
School of Life Sciences, Anhui University, Hefei, China.