Lipoxygenase structure [1]

PDB	scop	BSM	RELI Base	Header	¹
2sbl	2sbl	2sbl	2sbl	Lipoxygenase­1; soybean (Glycine max)	MMS94164

a	b

¹ Macromolecular Structures abstract. Full text is available to BioMedNet Members

The soybean lipoxygenase­1 [1] consists of a small N­terminal domain and a major C­terminal domain, which contains the active site. The N­terminal domain is an eight­stranded antiparallel ß­barrel associated with one ­helix. The C­terminal domain consists of 22 helices and two antiparallel ß­sheets. The two longest helices, helix 9 (43 amino acids) and helix 18 (30 amino acids) cross at the active site; both helices include internal stretches of ­helix (residues 494-506 in helix 9 and residues 685-690 in helix 18) that provide three His ligands to the active site iron. Two cavities in the major domain (cavities I and II) extend from the surface to the active site. The funnel­shaped cavity I may function as a dioxygen channel; the long narrow cavity II is presumably a substrate pocket. The active site iron is coordinated by His­499, His­504, His­690 and one oxygen of the C­terminal carboxyl group; in addition, the side chain oxygen of Asn­694 is weakly associated with the iron.

1. Ribbon representation of the soybean lipoxygenase­1 (PDB code 2SBL). Colour­codes: N­terminal domain (7-170) = violet; C­terminal domain (255-839) = dark green; helix 9 (474-516) = light green; helix 18 (672-701) = light blue.
2. Active site structure: ­helices 494-506 (yellow) and 685-690 (pink) and iron ligands His­499, His­504, His­690, Ile­839 and Asn­694 (orientation as a).

1. Boyington, J.C., Gaffney, B.J. and Amzel, L.M. (1993) The three­dimensional structure of an arachidonic acid 15­lipoxygenase. Science 260, 1482-1486.
2. Kraulis, P.J. (1991) MOLSCRIPT: a program to produce both detailed and schematic plots of protein structure. J. Appl. Crystallogr. 24, 946-950.

Bibliography on structural studies of lipoxygenases