3UZO

Crystal Structures of Branched-Chain Aminotransferase from Deinococcus radiodurans Complexes with alpha-Ketoisocaproate and L-Glutamate Suggest Its Radio-Resistance for Catalysis


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.263 
  • R-Value Work: 0.221 

wwPDB Validation 3D Report Full Report


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Literature

Crystal Structures of Complexes of the Branched-Chain Aminotransferase from Deinococcus radiodurans with alpha-Ketoisocaproate and L-Glutamate Suggest the Radiation Resistance of This Enzyme for Catalysis

Chen, C.D.Lin, C.H.Chuankhayan, P.Huang, Y.C.Hsieh, Y.C.Huang, T.F.Guan, H.H.Liu, M.Y.Chang, W.C.Chen, C.J.

(2012) J.Bacteriol. 194: 6206-6216

  • DOI: 10.1128/JB.01659-12
  • Primary Citation of Related Structures:  3UYY, 3UZB

  • PubMed Abstract: 
  • Branched-chain aminotransferases (BCAT), which utilize pyridoxal 5'-phosphate (PLP) as a cofactor, reversibly catalyze the transfer of the α-amino groups of three of the most hydrophobic branched-chain amino acids (BCAA), leucine, isoleucine, and val ...

    Branched-chain aminotransferases (BCAT), which utilize pyridoxal 5'-phosphate (PLP) as a cofactor, reversibly catalyze the transfer of the α-amino groups of three of the most hydrophobic branched-chain amino acids (BCAA), leucine, isoleucine, and valine, to α-ketoglutarate to form the respective branched-chain α-keto acids and glutamate. The BCAT from Deinococcus radiodurans (DrBCAT), an extremophile, was cloned and expressed in Escherichia coli for structure and functional studies. The crystal structures of the native DrBCAT with PLP and its complexes with L-glutamate and α-ketoisocaproate (KIC), respectively, have been determined. The DrBCAT monomer, comprising 358 amino acids, contains large and small domains connected with an interdomain loop. The cofactor PLP is located at the bottom of the active site pocket between two domains and near the dimer interface. The substrate (L-glutamate or KIC) is bound with key residues through interactions of the hydrogen bond and the salt bridge near PLP inside the active site pocket. Mutations of some interaction residues, such as Tyr71, Arg145, and Lys202, result in loss of the specific activity of the enzymes. In the interdomain loop, a dynamic loop (Gly173 to Gly179) clearly exhibits open and close conformations in structures of DrBCAT without and with substrates, respectively. DrBCAT shows the highest specific activity both in nature and under ionizing radiation, but with lower thermal stability above 60 °C, than either BCAT from Escherichia coli (eBCAT) or from Thermus thermophilus (HB8BCAT). The dimeric molecular packing and the distribution of cysteine residues at the active site and the molecular surface might explain the resistance to radiation but small thermal stability of DrBCAT.


    Organizational Affiliation

    Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu, Taiwan.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Branched-chain-amino-acid aminotransferase
A, B
358Deinococcus radiodurans (strain ATCC 13939 / DSM 20539 / JCM 16871 / LMG 4051 / NBRC 15346 / NCIMB 9279 / R1 / VKM B-1422)EC: 2.6.1.42
Find proteins for Q9RTX5 (Deinococcus radiodurans (strain ATCC 13939 / DSM 20539 / JCM 16871 / LMG 4051 / NBRC 15346 / NCIMB 9279 / R1 / VKM B-1422))
Go to UniProtKB:  Q9RTX5
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GLU
Query on GLU

Download SDF File 
Download CCD File 
A, B
GLUTAMIC ACID
C5 H9 N O4
WHUUTDBJXJRKMK-VKHMYHEASA-N
 Ligand Interaction
PLP
Query on PLP

Download SDF File 
Download CCD File 
A, B
PYRIDOXAL-5'-PHOSPHATE
VITAMIN B6 Phosphate
C8 H10 N O6 P
NGVDGCNFYWLIFO-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.263 
  • R-Value Work: 0.221 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 55.881α = 90.00
b = 75.980β = 105.98
c = 79.123γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data scaling
CNSphasing
HKL-2000data collection
CNSrefinement
HKL-2000data reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2012-12-12
    Type: Initial release