3DY5

Allene oxide synthase 8R-lipoxygenase from Plexaura homomalla

Summary for 3DY5

• Entry DOI: 10.2210/pdb3dy5/pdb
• Related: 1U5U 2FNQ
• Descriptor: Allene oxide synthase-lipoxygenase protein, FE (II) ION, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total)
• Functional Keywords: fusion protein, bi-functional enzyme, dioxygenase, fatty acid biosynthesis, heme, iron, lipid synthesis, lyase, membrane, metal-binding, multifunctional enzyme, oxidoreductase, oxylipin biosynthesis
• Biological source: Plexaura homomalla (Black sea rod)
• Cellular location: Cytoplasm: O16025
• Total number of polymer chains: 2
• Total formula weight: 245284.45

Authors

Gilbert, N.C.,Niebuhr, M.,Tsuruta, H.,Newcomer, M.E. (deposition date: 2008-07-25, release date: 2008-10-07, Last modification date: 2023-08-30)

Primary citation

Gilbert, N.C.,Niebuhr, M.,Tsuruta, H.,Bordelon, T.,Ridderbusch, O.,Dassey, A.,Brash, A.R.,Bartlett, S.G.,Newcomer, M.E.
A covalent linker allows for membrane targeting of an oxylipin biosynthetic complex.
Biochemistry, 47:10665-10676, 2008

PubMed Abstract: A naturally occurring bifunctional protein from Plexaura homomalla links sequential catalytic activities in an oxylipin biosynthetic pathway. The C-terminal lipoxygenase (LOX) portion of the molecule catalyzes the transformation of arachidonic acid (AA) to the corresponding 8 R-hydroperoxide, and the N-terminal allene oxide synthase (AOS) domain promotes the conversion of the hydroperoxide intermediate to the product allene oxide (AO). Small-angle X-ray scattering data indicate that in the absence of a covalent linkage the two catalytic domains that transform AA to AO associate to form a complex that recapitulates the structure of the bifunctional protein. The SAXS data also support a model for LOX and AOS domain orientation in the fusion protein inferred from a low-resolution crystal structure. However, results of membrane binding experiments indicate that covalent linkage of the domains is required for Ca (2+)-dependent membrane targeting of the sequential activities, despite the noncovalent domain association. Furthermore, membrane targeting is accompanied by a conformational change as monitored by specific proteolysis of the linker that joins the AOS and LOX domains. Our data are consistent with a model in which Ca (2+)-dependent membrane binding relieves the noncovalent interactions between the AOS and LOX domains and suggests that the C2-like domain of LOX mediates both protein-protein and protein-membrane interactions.

PubMed: 18785758
DOI: 10.1021/bi800751p

Experimental method

X-RAY DIFFRACTION (3.51 Å)