1JCI

Stabilization of the Engineered Cation-binding Loop in Cytochrome c Peroxidase (CcP)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.199 
  • R-Value Work: 0.158 

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This is version 1.4 of the entry. See complete history


Literature

Cation-induced stabilization of the engineered cation-binding loop in cytochrome c peroxidase (CcP).

Bhaskar, B.Bonagura, C.A.Li, H.Poulos, T.L.

(2002) Biochemistry 41: 2684-2693

  • DOI: 10.1021/bi011599y
  • Primary Citation of Related Structures:  
    1JCI

  • PubMed Abstract: 
  • We have previously shown that the K(+) site found in the proximal heme pocket of ascorbate peroxidase (APX) could be successfully engineered into the closely homologous cytochrome c peroxidase (CcP) [Bonagura et al., (1996) Biochemistry 35, 6107-6115; Bonagura et al ...

    We have previously shown that the K(+) site found in the proximal heme pocket of ascorbate peroxidase (APX) could be successfully engineered into the closely homologous cytochrome c peroxidase (CcP) [Bonagura et al., (1996) Biochemistry 35, 6107-6115; Bonagura et al. (1999) Biochemistry 38, 5538-5545]. In addition, specificity could be switched to binding Ca(2+) as found in other peroxidases [Bonagura et al. (1999) J. Biol. Chem. 274, 37827-37833]. The introduction of a proximal cation-binding site also promotes conversion of the Trp191 containing cation-binding loop from a "closed" to an "open" conformer. In the present study we have changed a crucial hinge residue of the cation-binding loop, Asn195, to Pro which stabilizes the loop, albeit, only in the presence of bound K(+). The crystal structure of this mutant, N195PK2, has been refined to 1.9 A. As predicted, introduction of this crucial hinge residue stabilizes the cation-binding loop in the presence of the bound K(+). As in earlier work, the characteristic EPR signal of Trp191 cation radical becomes progressively weaker with increasing [K(+)] and the lifetime of the Trp191 radical also has been considerably shortened in this mutant. This mutant CcP exhibits reduced enzyme activity, which could be titrated to lower levels with increasing [K(+)] when horse heart cytochrome c is the substrate. However, with yeast cytochrome c as the substrate, the mutant was as active as wild-type at low ionic strength, but 40-fold lower at high ionic strength. We attribute this difference to a change in the rate-limiting step as a function of ionic strength when yeast cytochrome c is the substrate.


    Related Citations: 
    • The Effects of an Engineered Cation Site on the Structure, Activity and EPR Properties of Cytochrome C Peroxidase
      Bonagura, C.A., Sundaramoorthy, M., Bhaskar, B., Poulos, T.L.
      (1999) Biochemistry 38: 5538
    • An Engineered Cation Site in Cytochrome C Peroxidase Alters the Reactivity of the Redox Active Tryptophan
      Bonagura, C.A., Sundaramoorthy, M., Pappa, H.S., Patterson, W.R., Poulos, T.L.
      (1996) Biochemistry 35: 6107

    Organizational Affiliation

    Department of Molecular Biology, University of California-Irvine, Irvine, California 92697-3900, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Cytochrome C PeroxidaseA294Saccharomyces cerevisiaeMutation(s): 5 
Gene Names: OPBYC
EC: 1.11.1.5
UniProt
Find proteins for P00431 (Saccharomyces cerevisiae (strain ATCC 204508 / S288c))
Explore P00431 
Go to UniProtKB:  P00431
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
HEM (Subject of Investigation/LOI)
Query on HEM

Download Ideal Coordinates CCD File 
C [auth A]PROTOPORPHYRIN IX CONTAINING FE
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
 Ligand Interaction
K
Query on K

Download Ideal Coordinates CCD File 
B [auth A]POTASSIUM ION
K
NPYPAHLBTDXSSS-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.199 
  • R-Value Work: 0.158 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 106.68α = 90
b = 75.34β = 90
c = 51.3γ = 90
Software Package:
Software NamePurpose
CNSrefinement
SCALEPACKdata scaling
CNSphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2002-03-06
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-10-04
    Changes: Refinement description
  • Version 1.4: 2018-01-31
    Changes: Database references