6DNM

The crystal structure of SatS c-terminal domain

• PDB DOI: https://doi.org/10.2210/pdb6DNM/pdb

• Classification: CHAPERONE
• Organism(s): Mycobacterium tuberculosis H37Rv
• Expression System: Escherichia coli BL21
• Mutation(s): No 


• Deposited: 2018-06-07 Released: 2019-01-23 
• Deposition Author(s): Hughes, R.C., Sacchettini, J.C., TB Structural Genomics Consortium (TBSGC)
• Funding Organization(s): National Institutes of Health/National Human Genome Research Institute (NIH/NHGRI)

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.40 Å
• R-Value Free: 
  0.231 (Depositor), 0.230 (DCC) 
• R-Value Work: 
  0.193 (Depositor), 0.200 (DCC) 
• R-Value Observed: 
  0.195 (Depositor) 

Literature

Mycobacterium tuberculosisSatS is a chaperone for the SecA2 protein export pathway.

Miller, B.K., Hughes, R., Ligon, L.S., Rigel, N.W., Malik, S., Anjuwon-Foster, B.R., Sacchettini, J.C., Braunstein, M.

(2019) Elife 8

• PubMed: 30604681 
• DOI: https://doi.org/10.7554/eLife.40063
• Primary Citation of Related Structures:  
  6DNM, 6DRQ


• PubMed Abstract: 
  

  The SecA2 protein export system is critical for the virulence of Mycobacterium tuberculosis . However, the mechanism of this export pathway remains unclear. Through a screen for suppressors of a secA2 mutant, we identified a new player in the mycobacterial SecA2 pathway that we named SatS for S ec A 2 ( t wo) S uppressor. In M. tuberculosis , SatS is required for the export of a subset of SecA2 substrates and for growth in macrophages. We further identify a role for SatS as a protein export chaperone. SatS exhibits multiple properties of a chaperone, including the ability to bind to and protect substrates from aggregation. Our structural studies of SatS reveal a distinct combination of a new fold and hydrophobic grooves resembling preprotein-binding sites of the SecB chaperone. These results are significant in better defining a molecular pathway for M. tuberculosis pathogenesis and in expanding our appreciation of the diversity among chaperones and protein export systems.

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Organizational Affiliation: 

Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, North Carolina, United States.

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors and generated by PISA (software)

Biological Assembly Evidence: gel filtration

Macromolecule Content

• Total Structure Weight: 21.18 kDa 
• Atom Count: 1,577 
• Modelled Residue Count: 187 
• Deposited Residue Count: 190 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Export chaperone SatS	A	190	Mycobacterium tuberculosis H37Rv	Mutation(s): 0  Gene Names: LH57_18085

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.40 Å
• R-Value Free:  0.231 (Depositor), 0.230 (DCC) 
• R-Value Work:  0.193 (Depositor), 0.200 (DCC) 
• R-Value Observed: 0.195 (Depositor) 

Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 48.867	α = 90
b = 50.58	β = 90
c = 76.465	γ = 90

Software Package:

Software Name	Purpose
PHENIX	refinement
HKL-3000	data reduction
HKL-3000	data scaling
PHENIX	phasing

Structure Validation

Entry History & Funding Information

Deposition Data

• Released Date: 2019-01-23 
Deposition Author(s): Hughes, R.C., Sacchettini, J.C., TB Structural Genomics Consortium (TBSGC)

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Funding Organization	Location	Grant Number
National Institutes of Health/National Human Genome Research Institute (NIH/NHGRI)	United States	PO1AI095208

Revision History  

• Version 1.0: 2019-01-23
  Type: Initial release
  
• Version 1.1: 2019-12-18
  Changes: Author supporting evidence
• Version 1.2: 2024-03-13
  Changes: Data collection, Database references