1PHC

CRYSTAL STRUCTURE OF SUBSTRATE-FREE PSEUDOMONAS PUTIDA CYTOCHROME P450

Summary for 1PHC

• Entry DOI: 10.2210/pdb1phc/pdb
• Descriptor: CYTOCHROME P450-CAM, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total)
• Functional Keywords: oxidoreductase(oxygenase)
• Biological source: Pseudomonas putida
• Cellular location: Cytoplasm : P00183
• Total number of polymer chains: 1
• Total formula weight: 47205.37

Authors

Poulos, T.L. (deposition date: 1992-07-27, release date: 1993-10-31, Last modification date: 2024-02-14)

Primary citation

Poulos, T.L.,Finzel, B.C.,Howard, A.J.
Crystal structure of substrate-free Pseudomonas putida cytochrome P-450.
Biochemistry, 25:5314-5322, 1986

PubMed Abstract: The crystal structure of Pseudomonas putida cytochrome P-450cam in the substrate-free form has been refined at 2.20-A resolution and compared to the substrate-bound form of the enzyme. In the absence of the substrate camphor, the P-450cam heme iron atom is hexacoordinate with the sulfur atom of Cys-357 providing one axial heme ligand and a water molecule or hydroxide ion providing the other axial ligand. A network of hydrogen-bonded solvent molecules occupies the substrate pocket in addition to the iron-linked aqua ligand. When a camphor molecule binds, the active site waters including the aqua ligand are displaced, resulting in a pentacoordinate high-spin heme iron atom. Analysis of the Fno camphor - F camphor difference Fourier and a quantitative comparison of the two refined structures reveal that no detectable conformational change results from camphor binding other than a small repositioning of a phenylalanine side chain that contacts the camphor molecule. However, large decreases in the mean temperature factors of three separate segments of the protein centered on Tyr-96, Thr-185, and Asp-251 result from camphor binding. This indicates that camphor binding decreases the flexibility in these three regions of the P-450cam molecule without altering the mean position of the atoms involved.

PubMed: 3768350
DOI: 10.1021/bi00366a049

Experimental method

X-RAY DIFFRACTION (1.6 Å)