3GAJ

Structure of a C-terminal deletion variant of a PduO-type ATP:corrinoid adenosyltransferase from Lactobacillus reuteri complexed with cobalamin and ATP


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.38 Å
  • R-Value Free: 0.182 
  • R-Value Work: 0.164 
  • R-Value Observed: 0.165 

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This is version 1.4 of the entry. See complete history


Literature

Residue Phe112 of the human-type corrinoid adenosyltransferase (PduO) enzyme of Lactobacillus reuteri is critical to the formation of the four-coordinate Co(II) corrinoid substrate and to the activity of the enzyme.

Mera, P.E.St Maurice, M.Rayment, I.Escalante-Semerena, J.C.

(2009) Biochemistry 48: 3138-3145

  • DOI: https://doi.org/10.1021/bi9000134
  • Primary Citation of Related Structures:  
    3GAH, 3GAI, 3GAJ

  • PubMed Abstract: 

    ATP:Corrinoid adenosyltransferases (ACAs) catalyze the transfer of the adenosyl moiety from ATP to cob(I)alamin via a four-coordinate cob(II)alamin intermediate. At present, it is unknown how ACAs promote the formation of the four-coordinate corrinoid species needed for activity. The published high-resolution crystal structure of the ACA from Lactobacillus reuteri (LrPduO) in complex with ATP and cob(II)alamin shows that the environment around the alpha face of the corrin ring consists of bulky hydrophobic residues. To understand how these residues promote the generation of the four-coordinate cob(II)alamin, variants of the human-type ACA enzyme from L. reuteri (LrPduO) were kinetically and structurally characterized. These studies revealed that residue Phe112 is critical in the displacement of 5,6-dimethylbenzimidazole (DMB) from its coordination bond with the Co ion of the ring, resulting in the formation of the four-coordinate species. An F112A substitution resulted in a 80% drop in the catalytic efficiency of the enzyme. The explanation for this loss of activity was obtained from the crystal structure of the mutant protein, which showed cob(II)alamin bound in the active site with DMB coordinated to the cobalt ion. The crystal structure of an LrPduO(F112H) variant showed a DMB-off/His-on interaction between the corrinoid and the enzyme, whose catalytic efficiency was 4 orders of magnitude lower than that of the wild-type protein. The analysis of the kinetic parameters of LrPduO(F112H) suggests that the F112H substitution negatively impacts product release. Substitutions of other hydrophobic residues in the Cbl binding pocket did not result in significant defects in catalytic efficiency in vitro; however, none of the variant enzymes analyzed in this work supported AdoCbl biosynthesis in vivo.


  • Organizational Affiliation

    Department of Bacteriology, University of Wisconsin, Madison, Wisconsin 53706, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Cobalamin adenosyltransferase PduO-like protein187Limosilactobacillus reuteriMutation(s): 0 
Gene Names: cobApduo
EC: 2.5.1.17
UniProt
Find proteins for Q50EJ2 (Limosilactobacillus reuteri)
Explore Q50EJ2 
Go to UniProtKB:  Q50EJ2
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ50EJ2
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.38 Å
  • R-Value Free: 0.182 
  • R-Value Work: 0.164 
  • R-Value Observed: 0.165 
  • Space Group: H 3
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 67.679α = 90
b = 67.679β = 90
c = 111.18γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
REFMACrefinement
PDB_EXTRACTdata extraction

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-07-07
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2012-10-24
    Changes: Non-polymer description
  • Version 1.3: 2017-11-01
    Changes: Advisory, Refinement description
  • Version 1.4: 2024-02-21
    Changes: Advisory, Data collection, Database references, Derived calculations