1KXN

Crystal Structure of Cytochrome c Peroxidase with a Proposed Electron Transfer Pathway Excised to Form a Ligand Binding Channel.


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.194 
  • R-Value Work: 0.187 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Excision of a proposed electron transfer pathway in cytochrome c peroxidase and its replacement by a ligand-binding channel.

Rosenfeld, R.J.Hays, A.M.Musah, R.A.Goodin, D.B.

(2002) Protein Sci. 11: 1251-1259

  • DOI: 10.1110/ps.4870102
  • Primary Citation of Related Structures:  1KXM

  • PubMed Abstract: 
  • A previously proposed electron transfer (ET) pathway in the heme enzyme cytochrome c peroxidase has been excised from the structure, leaving an open ligand-binding channel in its place. Earlier studies on cavity mutants of this enzyme have revealed s ...

    A previously proposed electron transfer (ET) pathway in the heme enzyme cytochrome c peroxidase has been excised from the structure, leaving an open ligand-binding channel in its place. Earlier studies on cavity mutants of this enzyme have revealed structural plasticity in this region of the molecule. Analysis of these structures has allowed the design of a variant in which the specific section of protein backbone representing a previously proposed ET pathway is accurately extracted from the protein. A crystal structure verified the creation of an open channel that overlays the removed segment, extending from the surface of the protein to the heme at the core of the protein. A number of heterocyclic cations were found to bind to the proximal-channel mutant with affinities that can be rationalized based on the structures. It is proposed that small ligands bind more weakly to the proximal-channel mutant than to the W191G cavity due to an increased off rate of the open channel, whereas larger ligands are able to bind to the channel mutant without inducing large conformational changes. The structure of benzimidazole bound to the proximal-channel mutant shows that the ligand accurately overlays the position of the tryptophan radical center that was removed from the wild-type enzyme and displaces four of the eight ordered solvent molecules seen in the empty cavity. Ligand binding also caused a small rearrangement of the redesigned protein loop, perhaps as a result of improved electrostatic interactions with the ligand. The engineered channel offers the potential for introducing synthetic replacements for the removed structure, such as sensitizer-linked substrates. These installed "molecular wires" could be used to rapidly initiate reactions, trap reactive intermediates, or answer unresolved questions about ET pathways.


    Organizational Affiliation

    Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
cytochrome c peroxidase
A
289Saccharomyces cerevisiae (strain ATCC 204508 / S288c)Gene Names: CCP1 (CCP, CPO)
EC: 1.11.1.5
Find proteins for P00431 (Saccharomyces cerevisiae (strain ATCC 204508 / S288c))
Go to UniProtKB:  P00431
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
HEM
Query on HEM

Download SDF File 
Download CCD File 
A
PROTOPORPHYRIN IX CONTAINING FE
HEME
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.8 Å
  • R-Value Free: 0.194 
  • R-Value Work: 0.187 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 106.800α = 90.00
b = 75.800β = 90.00
c = 51.100γ = 90.00
Software Package:
Software NamePurpose
X-GENdata scaling
SHELXLrefinement
X-GENdata reduction
XFITdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2002-03-06
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2017-10-11
    Type: Refinement description