Lipoxygenase

PDB file 1LOX

This file depicts 15-lipoxygenase from rabbit reticulocyte, co-crystallized with a competitive inhibitor (substrate analog). The structure was solved by S. A. Gillmor, A. Villasenor, R. J. Fletterick, E. Sigal, & M. F. Browner in 1998.

Suggested display options:

Display the protein as cartoons with color structure.
Identify the N-terminal domain that has a role in binding the enzyme to membranes. It has a b-barrel structure.
Look for hydrophobic residues Tyr15, Phe70, Leu71 found to be essential for membrane binding.

Select hetero-ligand, display as ball & stick, and color CPK, to visualize the analog of the substrate arachidonate (also selectable as 841).

Select atom FE display spacefill & change its color to green.

Select residue his, display as sticks, & color CPK.
What atoms serve as ligands to the iron?

An additional ligand to the iron is the protein's C-terminus.
Identify this residue, and display as ball & stick with color CPK.
What atoms of the C-terminal residue interact with the iron atom?

Questions:
Are residues surrounding the arachidonate analog largely polar or non-polar?
Why has no-one succeeded in crystallizing Lipoxygenase with the substrate arachidonate? What conditions might be necessary to do this?

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