6RAE image
Entry Detail
PDB ID:
6RAE
Keywords:
Title:
Structural analysis of the Salmonella type III secretion system ATPase InvC
Biological Source:
PDB Version:
Deposition Date:
2019-04-05
Release Date:
2019-08-21
Method Details:
Experimental Method:
Resolution:
2.05 Å
R-Value Free:
0.20
R-Value Work:
0.16
R-Value Observed:
0.16
Space Group:
P 65
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Secretory apparatus ATP synthase (Associated with virulence)
Chain IDs:A
Chain Length:363
Number of Molecules:1
Biological Source:Salmonella typhimurium (strain SL1344)
Primary Citation
Structural analysis of ligand-bound states of the Salmonella type III secretion system ATPase InvC.
Protein Sci. 28 1888 1901 (2019)
PMID: 31393998 DOI: 10.1002/pro.3704

Abstact

Translocation of virulence effector proteins through the type III secretion system (T3SS) is essential for the virulence of many medically relevant Gram-negative bacteria. The T3SS ATPases are conserved components that specifically recognize chaperone-effector complexes and energize effector secretion through the system. It is thought that functional T3SS ATPases assemble into a cylindrical structure maintained by their N-terminal domains. Using size-exclusion chromatography coupled to multi-angle light scattering and native mass spectrometry, we show that in the absence of the N-terminal oligomerization domain the Salmonella T3SS ATPase InvC can form monomers and dimers in solution. We also present for the first time a 2.05 å resolution crystal structure of InvC lacking the oligomerization domain (InvCΔ79) and map the amino acids suggested for ATPase intersubunit interaction, binding to other T3SS proteins and chaperone-effector recognition. Furthermore, we validate the InvC ATP-binding site by co-crystallization of InvCΔ79 with ATPγS (2.65 å) and ADP (2.80 å). Upon ATP-analogue recognition, these structures reveal remodeling of the ATP-binding site and conformational changes of two loops located outside of the catalytic site. Both loops face the central pore of the predicted InvC cylinder and are essential for the function of the T3SS ATPase. Our results present a fine functional and structural correlation of InvC and provide further details of the homo-oligomerization process and ATP-dependent conformational changes underlying the T3SS ATPase activity.

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