4Q1I

Structure and mechanism of a dehydratase/decarboxylase enzyme couple involved in polyketide beta-branching


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.195 
  • R-Value Observed: 0.198 

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This is version 1.2 of the entry. See complete history


Literature

Structure and mechanism of a dehydratase/decarboxylase enzyme couple involved in polyketide beta-methyl branch incorporation.

Nair, A.V.Robson, A.Ackrill, T.D.Till, M.Byrne, M.J.Back, C.R.Tiwari, K.Davies, J.A.Willis, C.L.Race, P.R.

(2020) Sci Rep 10: 15323-15323

  • DOI: https://doi.org/10.1038/s41598-020-71850-w
  • Primary Citation of Related Structures:  
    4Q1G, 4Q1H, 4Q1I, 4Q1J, 4Q1K

  • PubMed Abstract: 

    Complex polyketides of bacterial origin are biosynthesised by giant assembly-line like megaenzymes of the type 1 modular polyketide synthase (PKS) class. The trans-AT family of modular PKSs, whose biosynthetic frameworks diverge significantly from those of the archetypal cis-AT type systems represent a new paradigm in natural product enzymology. One of the most distinctive enzymatic features common to trans-AT PKSs is their ability to introduce methyl groups at positions β to the thiol ester in the growing polyketide chain. This activity is achieved through the action of a five protein HCS cassette, comprising a ketosynthase, a 3-hydroxy-3-methylglutaryl-CoA synthase, a dehydratase, a decarboxylase and a dedicated acyl carrier protein. Here we report a molecular level description, achieved using a combination of X-ray crystallography, in vitro enzyme assays and site-directed mutagenesis, of the bacillaene synthase dehydratase/decarboxylase enzyme couple PksH/PksI, responsible for the final two steps in β-methyl branch installation in this trans-AT PKS. Our work provides detailed mechanistic insight into this biosynthetic peculiarity and establishes a molecular framework for HCS cassette enzyme exploitation and manipulation, which has future potential value in guiding efforts in the targeted synthesis of functionally optimised 'non-natural' natural products.


  • Organizational Affiliation

    School of Biochemistry, University of Bristol, University Walk, Bristol, BS8 1TD, UK.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Polyketide biosynthesis enoyl-CoA isomerase PksI
A, B, C
268Bacillus subtilis subsp. subtilis str. 168Mutation(s): 1 
Gene Names: pksIBSU17170
EC: 4
UniProt
Find proteins for P40802 (Bacillus subtilis (strain 168))
Explore P40802 
Go to UniProtKB:  P40802
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP40802
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.195 
  • R-Value Observed: 0.198 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 81.91α = 90
b = 85.88β = 90
c = 126.8γ = 90
Software Package:
Software NamePurpose
MOLREPphasing
REFMACrefinement
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2015-05-06
    Type: Initial release
  • Version 1.1: 2023-05-24
    Changes: Database references, Derived calculations
  • Version 1.2: 2024-05-22
    Changes: Data collection