6BJ9

Crystal structure of Acat2 thiolase from Ascaris suum


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.53014 Å
  • R-Value Free: 0.160 
  • R-Value Work: 0.139 

wwPDB Validation 3D Report Full Report


This is version 1.0 of the entry. See complete history

Literature

Structural and Biochemical Studies of Substrate Selectivity in Ascaris suum Thiolases.

Blaisse, M.R.Fu, B.Chang, M.C.Y.

(2018) Biochemistry --: --

  • DOI: 10.1021/acs.biochem.7b01123
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Thiolases are a class of carbon-carbon bond forming enzymes with important applications in biotechnology and metabolic engineering as they provide a general method for the condensation of two acyl coenzyme A (CoA) substrates. As such, developing a gr ...

    Thiolases are a class of carbon-carbon bond forming enzymes with important applications in biotechnology and metabolic engineering as they provide a general method for the condensation of two acyl coenzyme A (CoA) substrates. As such, developing a greater understanding of their substrate selectivity would expand our ability to engineer the enzymatic or microbial production of a broad range of small-molecule targets. Here, we report the crystal structures and biochemical characterization of Acat2 and Acat5, two biosynthetic thiolases from Ascaris suum with varying selectivity toward branched compared to linear compounds. The structure of the Acat2-C91S mutant bound to propionyl-CoA shows that the terminal methyl group of the substrate, representing the α-branch point, is directed toward the conserved Phe 288 and Met 158 residues. In Acat5, the Phe ring is rotated to accommodate a hydroxyl-π interaction with an adjacent Thr side chain, decreasing space in the binding pocket and possibly accounting for its strong preference for linear substrates compared to Acat2. Comparison of the different Acat thiolase structures shows that Met 158 is flexible, adopting alternate conformations with the side chain rotated toward or away from a covering loop at the back of the active site. Mutagenesis of residues in the covering loop in Acat5 with the corresponding residues from Acat2 allows for highly increased accommodation of branched substrates, whereas the converse mutations do not significantly affect Acat2 substrate selectivity. Our results suggest an important contribution of second-shell residues to thiolase substrate selectivity and offer insights into engineering this enzyme class.


    Organizational Affiliation

    Department of Chemistry and ‡Department of Molecular and Cell Biology, University of California , Berkeley, California 94720-1460, United States.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Acetyl-CoA acetyltransferase A
A, B
393Ascaris suum
Find proteins for F1KYX0 (Ascaris suum)
Go to UniProtKB:  F1KYX0
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
K
Query on K

Download SDF File 
Download CCD File 
A, B
POTASSIUM ION
K
NPYPAHLBTDXSSS-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.53014 Å
  • R-Value Free: 0.160 
  • R-Value Work: 0.139 
  • Space Group: P 2 21 21
Unit Cell:
Length (Å)Angle (°)
a = 71.574α = 90.00
b = 88.123β = 90.00
c = 142.265γ = 90.00
Software Package:
Software NamePurpose
PHENIXrefinement
PHENIXphasing
PHENIXmodel building
Aimlessdata scaling
XDSdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationCountryGrant Number
National Science Foundation (United States)United StatesCHE-1413862

Revision History 

  • Version 1.0: 2018-02-07
    Type: Initial release