3TW6

Structure of Rhizobium etli pyruvate carboxylase T882A with the allosteric activator, acetyl coenzyme-A


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.189 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Interaction between the biotin carboxyl carrier domain and the biotin carboxylase domain in pyruvate carboxylase from Rhizobium etli.

Lietzan, A.D.Menefee, A.L.Zeczycki, T.N.Kumar, S.Attwood, P.V.Wallace, J.C.Cleland, W.W.St Maurice, M.

(2011) Biochemistry 50: 9708-9723

  • DOI: 10.1021/bi201277j
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Pyruvate carboxylase (PC) catalyzes the ATP-dependent carboxylation of pyruvate to oxaloacetate, an important anaplerotic reaction in mammalian tissues. To effect catalysis, the tethered biotin of PC must gain access to active sites in both the bioti ...

    Pyruvate carboxylase (PC) catalyzes the ATP-dependent carboxylation of pyruvate to oxaloacetate, an important anaplerotic reaction in mammalian tissues. To effect catalysis, the tethered biotin of PC must gain access to active sites in both the biotin carboxylase domain and the carboxyl transferase domain. Previous studies have demonstrated that a mutation of threonine 882 to alanine in PC from Rhizobium etli renders the carboxyl transferase domain inactive and favors the positioning of biotin in the biotin carboxylase domain. We report the 2.4 Å resolution X-ray crystal structure of the Rhizobium etli PC T882A mutant which reveals the first high-resolution description of the domain interaction between the biotin carboxyl carrier protein domain and the biotin carboxylase domain. The overall quaternary arrangement of Rhizobium etli PC remains highly asymmetrical and is independent of the presence of allosteric activator. While biotin is observed in the biotin carboxylase domain, its access to the active site is precluded by the interaction between Arg353 and Glu248, revealing a mechanism for regulating carboxybiotin access to the BC domain active site. The binding location for the biotin carboxyl carrier protein domain demonstrates that tethered biotin cannot bind in the biotin carboxylase domain active site in the same orientation as free biotin, helping to explain the difference in catalysis observed between tethered biotin and free biotin substrates in biotin carboxylase enzymes. Electron density located in the biotin carboxylase domain active site is assigned to phosphonoacetate, offering a probable location for the putative carboxyphosphate intermediate formed during biotin carboxylation. The insights gained from the T882A Rhizobium etli PC crystal structure provide a new series of catalytic snapshots in PC and offer a revised perspective on catalysis in the biotin-dependent enzyme family.


    Organizational Affiliation

    Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin 53201, United States.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Pyruvate carboxylase protein
A, B, C, D
1165Rhizobium etli (strain CFN 42 / ATCC 51251)Mutation(s): 1 
Gene Names: pyc
EC: 6.4.1.1
Find proteins for Q2K340 (Rhizobium etli (strain CFN 42 / ATCC 51251))
Go to UniProtKB:  Q2K340
Small Molecules
Ligands 7 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ZN
Query on ZN

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A, B, C, D
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
ADP
Query on ADP

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A, B, C, D
ADENOSINE-5'-DIPHOSPHATE
C10 H15 N5 O10 P2
XTWYTFMLZFPYCI-KQYNXXCUSA-N
 Ligand Interaction
CL
Query on CL

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A, B, C, D
CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
 Ligand Interaction
COA
Query on COA

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A, C
COENZYME A
C21 H36 N7 O16 P3 S
RGJOEKWQDUBAIZ-IBOSZNHHSA-N
 Ligand Interaction
PAE
Query on PAE

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C
PHOSPHONOACETIC ACID
C2 H5 O5 P
XUYJLQHKOGNDPB-UHFFFAOYSA-N
 Ligand Interaction
MG
Query on MG

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A, B, C, D
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
BTI
Query on BTI

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B
5-(HEXAHYDRO-2-OXO-1H-THIENO[3,4-D]IMIDAZOL-6-YL)PENTANAL
C10 H16 N2 O2 S
ARDNWGMSCXSPBF-CIUDSAMLSA-N
 Ligand Interaction
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
KCX
Query on KCX
A, B, C, D
L-PEPTIDE LINKINGC7 H14 N2 O4LYS
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Free: 0.235 
  • R-Value Work: 0.189 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 370.445α = 90.00
b = 91.550β = 134.71
c = 261.354γ = 90.00
Software Package:
Software NamePurpose
PHASERphasing
REFMACrefinement
HKL-2000data scaling
HKL-2000data reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2011-10-19
    Type: Initial release
  • Version 1.1: 2011-12-28
    Type: Database references