1U16

Crystal structure of a duck-delta-crystallin-1 double loop mutant (DLM) in complex with sulfate


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.265 
  • R-Value Work: 0.212 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

A duck delta1 crystallin double loop mutant provides insight into residues important for argininosuccinate lyase activity.

Tsai, M.Sampaleanu, L.M.Greene, C.Creagh, L.Haynes, C.Howell, P.L.

(2004) Biochemistry 43: 11672-11682

  • DOI: 10.1021/bi0489006
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Delta-crystallin is directly related to argininosuccinate lyase (ASL), and catalyzes the reversible hydrolysis of argininosuccinate to arginine and fumarate. Two delta-crystallin isoforms exist in duck lenses, delta1 and delta2, which are 94% identic ...

    Delta-crystallin is directly related to argininosuccinate lyase (ASL), and catalyzes the reversible hydrolysis of argininosuccinate to arginine and fumarate. Two delta-crystallin isoforms exist in duck lenses, delta1 and delta2, which are 94% identical in amino acid sequence. Although the sequences of duck delta2-crystallin (ddeltac2) and duck delta1-crystallin (ddeltac1) are 69 and 71% identical to that of human ASL, respectively, only ddeltac2 has maintained ASL activity. Domain exchange experiments and comparisons of various delta-crystallin structures have suggested that the amino acid substitutions in the 20's (residues 22-31) and 70's (residues 74-89) loops of ddeltac1 are responsible for the loss of enzyme activity in this isoform. To test this hypothesis, a double loop mutant (DLM) of ddeltac1 was constructed in which all the residues that differ between the two isoforms in the 20's and 70's loops were mutated to those of ddeltac2. Contrary to expectations, kinetic analysis of the DLM found that it was enzymatically inactive. Furthermore, binding of argininosuccinate by the DLM, as well as the ddeltac1, could not be detected by isothermal titration calorimetry (ITC). To examine the conformation of the 20's and 70's loops in the DLM, and to understand why the DLM is unable to bind the substrate, its structure was determined to 2.5 A resolution. Comparison of this structure with both wild-type ddeltac1 and ddeltac2 structures reveals that the conformations of the 20's and 70's loops in the DLM mutant are very similar to those of ddeltac2. This suggests that the five amino acid substitutions in domain 1 which lie outside of the two loop regions and which are different in the DLM, and ddeltac2, must be important enzymatically. The structure of the DLM in complex with sulfate was also determined to 2.2 A resolution. This structure demonstrates that the conformational changes of the 280's loop and domain 3, previously observed in ddeltac1, also occur in the DLM upon sulfate binding, reinforcing the hypothesis that these events may occur in the active ddeltac2 protein during catalysis.


    Organizational Affiliation

    Structural Biology and Biochemistry, Research Institute, Hospital for Sick Children, 555 University Avenue, Toronto, Ontario M5G 1X8, Canada.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Delta crystallin I
A
472Anas platyrhynchosMutation(s): 11 
Gene Names: ASL1
Find proteins for P24057 (Anas platyrhynchos)
Go to UniProtKB:  P24057
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
CL
Query on CL

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Download CCD File 
A
CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
 Ligand Interaction
MES
Query on MES

Download SDF File 
Download CCD File 
A
2-(N-MORPHOLINO)-ETHANESULFONIC ACID
C6 H13 N O4 S
SXGZJKUKBWWHRA-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.265 
  • R-Value Work: 0.212 
  • Space Group: P 4 21 2
Unit Cell:
Length (Å)Angle (°)
a = 133.280α = 90.00
b = 133.280β = 90.00
c = 73.910γ = 90.00
Software Package:
Software NamePurpose
CNSrefinement
d*TREKdata scaling
CNSphasing
CrystalCleardata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2004-10-05
    Type: Initial release
  • Version 1.1: 2008-04-30
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Derived calculations, Version format compliance