3CP4

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


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Observed: 0.163 

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

  • DOI: 10.1021/bi00112a008
  • Primary Citation of Related Structures:  
    4CP4, 3CP4, 2CP4

  • 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), Thr252 is highly conserved among P-450 enzymes ...

    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: 
    • X-Ray Crystallographic Structural Studies of Cytochrome P450-Cam+
      Raag, R., Poulos, T.L.
      () To be published --: --
    • 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
    • Crystal Structure of the Carbon Monoxy-Substrate-Cytochrome P450-Cam Ternary Complex
      Raag, R., Poulos, T.L.
      (1989) Biochemistry 28: 7586
    • 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

    Organizational Affiliation

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



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
CYTOCHROME P450-CAMA414Pseudomonas putidaMutation(s): 0 
Gene Names: POTENTIALcamCcyp101
EC: 1.14.15.1
UniProt
Find proteins for P00183 (Pseudomonas putida)
Explore P00183 
Go to UniProtKB:  P00183
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 
B [auth A]PROTOPORPHYRIN IX CONTAINING FE
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
 Ligand Interaction
ADM
Query on ADM

Download Ideal Coordinates CCD File 
C [auth A]ADAMANTANE
C10 H16
ORILYTVJVMAKLC-YNFQOJQRSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Observed: 0.163 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 108.67α = 90
b = 103.9β = 90
c = 36.38γ = 90
Software Package:
Software NamePurpose
PROFFTrefinement

Structure Validation

View Full Validation Report




Entry History 

Deposition Data

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

Revision History  (Full details and data files)

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