4CP4

CRYSTAL STRUCTURE OF THE CYTOCHROME P450-CAM ACTIVE SITE MUTANT THR252ALA


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Crystal structure of the cytochrome P-450CAM active site mutant Thr252Ala.

Raag, R.Martinis, S.A.Sligar, S.G.Poulos, T.L.

(1991) Biochemistry 30: 11420-11429

  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The crystal structure of a cytochrome P-450CAM site-directed mutant in which the active site Thr252 has been replaced with an Ala (Thr252Ala) has been refined to an R factor of 0.18 at 2.2 A. According to sequence alignments (Nelson & Strobel, 1989), ...

    The crystal structure of a cytochrome P-450CAM site-directed mutant in which the active site Thr252 has been replaced with an Ala (Thr252Ala) has been refined to an R factor of 0.18 at 2.2 A. According to sequence alignments (Nelson & Strobel, 1989), Thr252 is highly conserved among P-450 enzymes. The crystallographic structure of ferrous camphor- and carbon monoxide-bound P-450CAM (Raag & Poulos, 1989b) suggests that Thr252 is a key active site residue, forming part of the dioxygen-binding site. Mutation of the active site threonine to alanine produces an enzyme in which substrate hydroxylation is uncoupled from electron transfer. Specifically, hydrogen peroxide and "excess" water are produced instead of the product, 5-exo-hydroxycamphor. The X-ray structure has revealed that a local distortion in the distal helix between Gly248 and Thr252 becomes even more severe in the Thr252Ala mutant. Furthermore, a solvent molecule not present in the native enzyme is positioned in the dioxygen-binding region of the mutant enzyme active site. In this location, the solvent molecule could sterically interfere with and destabilize dioxygen binding. In addition, the active site solvent molecule is connected, via a network of hydrogen bonds, with an internal solvent channel which links distal helix residues to a buried Glu side chain. Thus, solvent protons appear to be much more accessible to dioxygen in the mutant than in the wild-type enzyme, a factor which may promote hydrogen peroxide and/or water production instead of substrate hydroxylation. On the basis of crystallographic and mutagenesis data, a proton delivery pathway involving residues Lys178/Arg186, Asp251, and Thr252 is proposed for wild-type P-450CAM. Coordinates of structures discussed in this paper have been submitted to the Brookhaven Protein Data Bank (Bernstein et al., 1977).


    Related Citations: 
    • Crystal Structure of the Carbon Monoxy-Substrate-Cytochrome P450-Cam Ternary Complex
      Raag, R.,Poulos, T.L.
      (1989) Biochemistry 28: 7586
    • Crystal Structures of Cytochrome P450-Cam Complexed with Camphane, Thiocamphor, and Adamantane: Factors Controlling P450 Substrate Hydroxylation
      Raag, R.,Poulos, T.L.
      (1991) Biochemistry 30: 2674
    • The Structural Basis for Substrate-Induced Changes in Redox Potential and Spin Equilibrium in Cytochrome P450(Cam)
      Raag, R.,Poulos, T.L.
      (1989) Biochemistry 28: 917
    • X-Ray Crystallographic Structural Studies of Cytochrome P450-Cam+
      Raag, R.,Poulos, T.L.
      () TO BE PUBLISHED --: --


    Organizational Affiliation

    Maryland Biotechnology Institute, University of Maryland, Shady Grove, Rockville, Maryland 20850.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
CYTOCHROME P450-CAM
A
414Pseudomonas putidaMutation(s): 0 
Gene Names: camC (cyp101)
EC: 1.14.15.1
Find proteins for P00183 (Pseudomonas putida)
Go to UniProtKB:  P00183
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CAM
Query on CAM

Download SDF File 
Download CCD File 
A
CAMPHOR
C10 H16 O
DSSYKIVIOFKYAU-XCBNKYQSSA-N
 Ligand Interaction
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: 2.1 Å
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 108.670α = 90.00
b = 103.900β = 90.00
c = 36.380γ = 90.00
Software Package:
Software NamePurpose
PROFFTrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 1991-06-04 
  • Released Date: 1993-01-15 
  • Deposition Author(s): Raag, R., Poulos, T.L.

Revision History 

  • Version 1.0: 1993-01-15
    Type: Initial release
  • Version 1.1: 2008-03-25
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2017-11-29
    Type: Derived calculations, Other