2IFV

Crystal structure of an active site mutant, C473D, of CDC25B phosphatase catalytic domain


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.60 Å
  • R-Value Free: 0.192 
  • R-Value Work: 0.179 
  • R-Value Observed: 0.179 

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


Literature

Kinetic and structural studies of specific protein-protein interactions in substrate catalysis by Cdc25B phosphatase.

Sohn, J.Buhrman, G.Rudolph, J.

(2007) Biochemistry 46: 807-818

  • DOI: https://doi.org/10.1021/bi061257y
  • Primary Citation of Related Structures:  
    2IFD, 2IFV

  • PubMed Abstract: 

    Using a combination of steady-state and single-turnover kinetics, we probe substrate association, dissociation, and chemistry for the reaction of Cdc25B phosphatase with its Cdk2-pTpY/CycA protein substrate. The rate constant for substrate association for the wild-type enzyme is 1.3 x 10(6) M(-1) s(-1). The rate constant for dissociation is slow compared to the rate constant for phosphate transfer to form the phospho-enzyme intermediate (k2 = 1.1 s(-1)), making Cdk2-pTpY/CycA a sticky substrate. Compared to the wild type, all hotspot mutants of residues at the remote docking site that specifically affect catalysis with the protein substrate (Arg488, Arg492, and Tyr497 on Cdc25B and Asp206 on Cdk2) have greatly slowed rate constants of association (70- to 4500-fold), and some mutants have decreased k2 values compared to that of the wild type. Most dramatically, R492L, despite showing no significant changes in a crystal structure at 2.0 A resolution, has an approximately 100-fold decrease in k2 compared to that of wild-type Cdc25B. The active site C473S mutant binds tightly to and dissociates slowly from Cdk2-pTpY/CycA (Kd = 10 nM, k(off) = 0.01 s(-1)). In contrast, the C473D mutant, despite showing only localized perturbations in the active site at 1.6 A resolution, has a much weaker affinity and dissociates rapidly (Kd of 2 microM, k(off) > 2 s(-1)) from the protein substrate. Overall, we demonstrate that the association of Cdc25B with its Cdk2-pTpY/CycA substrate is governed to a significant extent by the interactions of the remote hotspot residues, whereas dissociation is governed by interactions at the active site.


  • Organizational Affiliation

    Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
M-phase inducer phosphatase 2175Homo sapiensMutation(s): 1 
Gene Names: CDC25BCDC25HU2
EC: 3.1.3.48
UniProt & NIH Common Fund Data Resources
Find proteins for P30305 (Homo sapiens)
Explore P30305 
Go to UniProtKB:  P30305
PHAROS:  P30305
GTEx:  ENSG00000101224 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP30305
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.60 Å
  • R-Value Free: 0.192 
  • R-Value Work: 0.179 
  • R-Value Observed: 0.179 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 49.895α = 90
b = 71.189β = 90
c = 73.87γ = 90
Software Package:
Software NamePurpose
CNSrefinement
HKL-2000data reduction
HKL-2000data scaling
CNSphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-02-27
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2021-10-20
    Changes: Database references, Derived calculations
  • Version 1.4: 2023-08-30
    Changes: Data collection, Refinement description