3KX5

Crystal structure of Bacillus megaterium BM3 heme domain mutant F261E


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.69 Å
  • R-Value Free: 0.208 
  • R-Value Work: 0.174 
  • R-Value Observed: 0.175 

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Ligand Structure Quality Assessment 


This is version 1.3 of the entry. See complete history


Literature

Glutamate-haem ester bond formation is disfavoured in flavocytochrome P450 BM3: characterization of glutamate substitution mutants at the haem site of P450 BM3.

Girvan, H.M.Levy, C.W.Williams, P.Fisher, K.Cheesman, M.R.Rigby, S.E.Leys, D.Munro, A.W.

(2010) Biochem J 427: 455-466

  • DOI: https://doi.org/10.1042/BJ20091603
  • Primary Citation of Related Structures:  
    3KX3, 3KX4, 3KX5

  • PubMed Abstract: 

    Bacillus megaterium flavocytochrome P450 BM3 (CYP102A1) is a biotechnologically important cytochrome P450/P450 reductase fusion enzyme. Mutants I401E, F261E and L86E were engineered near the haem 5-methyl group, to explore the ability of the glutamate carboxylates to form ester linkages with the methyl group, as observed for eukaryotic CYP4 relatives. Although no covalent linkage was detected, mutants displayed marked alterations in substrate/inhibitor affinity, with L86E and I401E mutants having lower Kd values for arachidonic acid and dodecanoic (lauric) acid than WT (wild-type) BM3. All mutations induced positive shifts in haem Fe(III)/Fe(II) potential, with substrate-free I401E (-219 mV) being >170 mV more positive than WT BM3. The elevated potential stimulated FMN-to-haem electron transfer ~2-fold (to 473 s-1) in I401E, and resulted in stabilization of Fe(II)O2 complexes in the I401E and L86E P450s. EPR demonstrated some iron co-ordination by glutamate carboxylate in L86E and F261E mutants, indicating structural plasticity in the haem domains. The Fe(II)O2 complex is EPR-silent, probably resulting from antiferromagnetic coupling between Fe(III) and bound superoxide in a ferric superoxo species. Structural analysis of mutant haem domains revealed modest rearrangements, including altered haem propionate interactions that may underlie the thermodynamic perturbations observed. The mutant flavocytochromes demonstrated WT-like hydroxylation of dodecanoic acid, but regioselectivity was skewed towards omega-3 hydroxydodecanoate formation in F261E and towards omega-1 hydroxydodecanoate production in I401E. Our data point strongly to a likelihood that glutamate-haem linkages are disfavoured in this most catalytically efficient P450, possibly due to the absence of a methylene radical species during catalysis.


  • Organizational Affiliation

    Manchester Interdisciplinary Biocentre, University of Manchester, UK. Hazel.Girvan@Manchester.ac.uk


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Bifunctional P-450/NADPH-P450 reductase
A, B
470Priestia megateriumMutation(s): 1 
Gene Names: CYP102A1cyp102
EC: 1.14.14.1
UniProt
Find proteins for P14779 (Priestia megaterium (strain ATCC 14581 / DSM 32 / CCUG 1817 / JCM 2506 / NBRC 15308 / NCIMB 9376 / NCTC 10342 / NRRL B-14308 / VKM B-512 / Ford 19))
Explore P14779 
Go to UniProtKB:  P14779
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP14779
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.69 Å
  • R-Value Free: 0.208 
  • R-Value Work: 0.174 
  • R-Value Observed: 0.175 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 59.72α = 90
b = 153.8β = 94.46
c = 60.13γ = 90
Software Package:
Software NamePurpose
DNAdata collection
PHENIXmodel building
PHENIXrefinement
XDSdata reduction
XSCALEdata scaling
PHENIXphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2010-05-19
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2021-11-10
    Changes: Database references, Derived calculations
  • Version 1.3: 2024-05-29
    Changes: Data collection