6j18 | pdb_00006j18

ATPase

spinqualitylabelsall models 6j18, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6j18 is a 1 chain structure with sequence from Myctu. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ATP, MG Gene: eccC5, Rv1783 (MYCTU) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Type VII secretion systems (T7SSs) are found in many disease related bacteria including Mycobacterium tuberculosis (Mtb). ESX-1 [early secreted antigen 6 kilodaltons (ESAT-6) system 1] is one of the five subtypes (ESX-1~5) of T7SSs in Mtb, where it delivers virulence factors into host macrophages during infection. However, little is known about the molecular details as to how this occurs. Here, we provide high-resolution crystal structures of the C-terminal ATPase3 domains of EccC subunits from four different Mtb T7SS subtypes. These structures adopt a classic RecA-like a/beta fold with a conserved Mg-ATP binding site. The structure of EccCb1 in complex with the C-terminal peptide of EsxB identifies the location of substrate recognition site and shows how the specific signaling module "LxxxMxF" for Mtb ESX-1 binds to this site resulting in a translation of the bulge loop. A comparison of all the ATPase3 structures shows there are significant differences in the shape and composition of the signal recognition pockets across the family, suggesting that distinct signaling sequences of substrates are required to be specifically recognized by different T7SSs. A hexameric model of the EccC-ATPase3 is proposed and shows the recognition pocket is located near the central substrate translocation channel. The diameter of the channel is ~25-A, with a size that would allow helix-bundle shaped substrate proteins to bind and pass through. Thus, our work provides new molecular insights into substrate recognition for Mtb T7SS subtypes and also a possible transportation mechanism for substrate and/or virulence factor secretion. Structural insights into substrate recognition by the type VII secretion system.,Wang S, Zhou K, Yang X, Zhang B, Zhao Y, Xiao Y, Yang X, Yang H, Guddat LW, Li J, Rao Z Protein Cell. 2019 Nov 23. pii: 10.1007/s13238-019-00671-z. doi:, 10.1007/s13238-019-00671-z. PMID:31758528 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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