5ONC

Catabolism of the Cholesterol Side Chain in Mycobacterium tuberculosis is Controlled by a Redox-Sensitive Thiol Switch


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.19 Å
  • R-Value Free: 0.226 
  • R-Value Work: 0.182 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Catabolism of the Cholesterol Side Chain in Mycobacterium tuberculosis Is Controlled by a Redox-Sensitive Thiol Switch.

Lu, R.Schaefer, C.M.Nesbitt, N.M.Kuper, J.Kisker, C.Sampson, N.S.

(2017) ACS Infect Dis 3: 666-675

  • DOI: 10.1021/acsinfecdis.7b00072

  • PubMed Abstract: 
  • Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), is a highly successful human pathogen and has infected approximately one-third of the world's population. Multiple drug resistant (MDR) and extensively drug resistant (XDR) T ...

    Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), is a highly successful human pathogen and has infected approximately one-third of the world's population. Multiple drug resistant (MDR) and extensively drug resistant (XDR) TB strains and coinfection with HIV have increased the challenges of successfully treating this disease pandemic. The metabolism of host cholesterol by Mtb is an important factor for both its virulence and pathogenesis. In Mtb, the cholesterol side chain is degraded through multiple cycles of β-oxidation and FadA5 (Rv3546) catalyzes side chain thiolysis in the first two cycles. Moreover, FadA5 is important during the chronic stage of infection in a mouse model of Mtb infection. Here, we report the redox control of FadA5 catalytic activity that results from reversible disulfide bond formation between Cys59-Cys91 and Cys93-Cys377. Cys93 is the thiolytic nucleophile, and Cys377 is the general acid catalyst for cleavage of the β-keto-acyl-CoA substrate. The disulfide bond formed between the two catalytic residues Cys93 and Cys377 blocks catalysis. The formation of the disulfide bonds is accompanied by a large domain swap at the FadA5 dimer interface that serves to bring Cys93 and Cys377 in close proximity for disulfide bond formation. The catalytic activity of FadA5 has a midpoint potential of -220 mV, which is close to the Mtb mycothiol potential in the activated macrophage. The redox profile of FadA5 suggests that FadA5 is fully active when Mtb resides in the unactivated macrophage to maximize flux into cholesterol catabolism. Upon activation of the macrophage, the oxidative shift in the mycothiol potential will decrease the thiolytic activity by 50%. Thus, the FadA5 midpoint potential is poised to rapidly restrict cholesterol side chain degradation in response to oxidative stress from the host macrophage environment.


    Organizational Affiliation

    Rudolf Virchow Center for Experimental Biomedicine, Institute for Structural Biology, University of Würzburg , Josef-Schneider-Str. 2, Würzburg, D-97080, Germany.,Stellenbosch Institute for Advanced Study (STIAS), Wallenberg Research Centre at Stellenbosch University , Stellenbosch, 7600, South Africa.,Department of Chemistry, Stony Brook University , Stony Brook, New York 11794-3400, United States.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Steroid 3-ketoacyl-CoA thiolase
A, B
399Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv)Mutation(s): 0 
Gene Names: fadA5
EC: 2.3.1.16
Find proteins for I6XHI4 (Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv))
Go to UniProtKB:  I6XHI4
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CL
Query on CL

Download SDF File 
Download CCD File 
A, B
CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.19 Å
  • R-Value Free: 0.226 
  • R-Value Work: 0.182 
  • Space Group: P 63 2 2
Unit Cell:
Length (Å)Angle (°)
a = 120.289α = 90.00
b = 120.289β = 90.00
c = 206.030γ = 120.00
Software Package:
Software NamePurpose
iMOSFLMdata reduction
REFMACrefinement
PHASERphasing
Aimlessdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of HealthUnited StatesAI092455
National Institutes of HealthUnited StatesRR021008
German Research FoundationGermanySFB630
German Research FoundationGermanyFZ82

Revision History 

  • Version 1.0: 2017-08-23
    Type: Initial release
  • Version 1.1: 2017-09-20
    Type: Author supporting evidence, Database references