PDBsum entry 1phc

Oxidoreductase(oxygenase)

PDB id: 1phc

Contents

Protein chain

405 a.a.

Ligands

HEM

Waters ×192

References listed in PDB file

Key reference

• Title: Crystal structure of substrate-Free pseudomonas putida cytochrome p-450.
• Authors: T.L.Poulos, B.C.Finzel, A.J.Howard.
• Ref.: Biochemistry, 1986, 25, 5314-5322. [DOI no: 10.1021/bi00366a049]
• PubMed id: 3768350

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.

Secondary reference #1

• Title: Inhibitor-Induced conformational change in cytochrome p-450cam.
• Authors: R.Raag, H.Li, B.C.Jones, T.L.Poulos.
• Ref.: Biochemistry, 1993, 32, 4571-4578. [DOI no: 10.1021/bi00068a013]
• PubMed id: 8485133

Secondary reference #2

• Title: Crystal structures of metyrapone- And phenylimidazole-Inhibited complexes of cytochrome p-450cam.
• Authors: T.L.Poulos, A.J.Howard.
• Ref.: Biochemistry, 1987, 26, 8165-8174. [DOI no: 10.1021/bi00399a022]
• PubMed id: 3442650