3L02

Crystal structure of N-acetyl-L-ornithine transcarbamylase E92A mutant complexed with carbamyl phosphate and N-succinyl-L-norvaline


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.189 

Starting Model: experimental
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This is version 1.4 of the entry. See complete history


Literature

A single mutation in the active site swaps the substrate specificity of N-acetyl-L-ornithine transcarbamylase and N-succinyl-L-ornithine transcarbamylase.

Shi, D.Yu, X.Cabrera-Luque, J.Chen, T.Y.Roth, L.Morizono, H.Allewell, N.M.Tuchman, M.

(2007) Protein Sci 16: 1689-1699

  • DOI: https://doi.org/10.1110/ps.072919907
  • Primary Citation of Related Structures:  
    2G7M, 3L02, 3L04, 3L05, 3L06

  • PubMed Abstract: 

    Transcarbamylases catalyze the transfer of the carbamyl group from carbamyl phosphate (CP) to an amino group of a second substrate such as aspartate, ornithine, or putrescine. Previously, structural determination of a transcarbamylase from Xanthomonas campestris led to the discovery of a novel N-acetylornithine transcarbamylase (AOTCase) that catalyzes the carbamylation of N-acetylornithine. Recently, a novel N-succinylornithine transcarbamylase (SOTCase) from Bacteroides fragilis was identified. Structural comparisons of AOTCase from X. campestris and SOTCase from B. fragilis revealed that residue Glu92 (X. campestris numbering) plays a critical role in distinguishing AOTCase from SOTCase. Enzymatic assays of E92P, E92S, E92V, and E92A mutants of AOTCase demonstrate that each of these mutations converts the AOTCase to an SOTCase. Similarly, the P90E mutation in B. fragilis SOTCase (equivalent to E92 in X. campestris AOTCase) converts the SOTCase to AOTCase. Hence, a single amino acid substitution is sufficient to swap the substrate specificities of AOTCase and SOTCase. X-ray crystal structures of these mutants in complexes with CP and N-acetyl-L-norvaline (an analog of N-acetyl-L-ornithine) or N-succinyl-L-norvaline (an analog of N-succinyl-L-ornithine) substantiate this conversion. In addition to Glu92 (X. campestris numbering), other residues such as Asn185 and Lys30 in AOTCase, which are involved in binding substrates through bridging water molecules, help to define the substrate specificity of AOTCase. These results provide the correct annotation (AOTCase or SOTCase) for a set of the transcarbamylase-like proteins that have been erroneously annotated as ornithine transcarbamylase (OTCase, EC 2.1.3.3).


  • Organizational Affiliation

    Children's National Medical Center, The George Washington University, Washington, DC 20010, USA. dshi@cnmcresearch.org


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
N-acetylornithine carbamoyltransferase359Xanthomonas campestris pv. campestris str. ATCC 33913Mutation(s): 1 
Gene Names: argFargF'XCC2249
EC: 2.1.3.9
UniProt
Find proteins for Q8P8J2 (Xanthomonas campestris pv. campestris (strain ATCC 33913 / DSM 3586 / NCPPB 528 / LMG 568 / P 25))
Explore Q8P8J2 
Go to UniProtKB:  Q8P8J2
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ8P8J2
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
KCX
Query on KCX
A
L-PEPTIDE LINKINGC7 H14 N2 O4LYS
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.189 
  • Space Group: I 21 3
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 129.421α = 90
b = 129.421β = 90
c = 129.421γ = 90
Software Package:
Software NamePurpose
CNSrefinement
PDB_EXTRACTdata extraction
HKL-2000data collection
HKL-2000data reduction
HKL-2000data scaling
CNSphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2010-03-31
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2021-10-13
    Changes: Database references, Derived calculations
  • Version 1.3: 2023-09-06
    Changes: Data collection, Refinement description
  • Version 1.4: 2023-11-22
    Changes: Data collection