PDBsum entry 3dy5

Lyase, oxidoreductase

PDB id: 3dy5

Contents

Protein chains

1002 a.a. *

Ligands

HEM ×2

Metals

FE2 ×2

* Residue conservation analysis

PDB id:

3dy5

Name:

Lyase, oxidoreductase

Title:

Allene oxide synthase 8r-lipoxygenase from plexaura homomalla

Structure:

Allene oxide synthase-lipoxygenase protein. Chain: a, c. Synonym: [includes: allene oxide synthase (ec 4.2.1.92) (hydroperoxidehydrase), and arachidonate 8-lipoxygenase (ec 1.13.11.40)]. Engineered: yes

Source:

Plexaura homomalla. Black sea rod. Organism_taxid: 47982. Expressed in: escherichia coli.

Resolution:

3.51Å R-factor: 0.275 R-free: 0.322

Authors:

N.C.Gilbert,M.Niebuhr,H.Tsuruta,M.E.Newcomer

Key ref:

N.C.Gilbert et al. (2008). A covalent linker allows for membrane targeting of an oxylipin biosynthetic complex. Biochemistry, 47, 10665-10676. PubMed id: 18785758

Date:

25-Jul-08 Release date: 07-Oct-08

Protein chains

O16025  (AOSL_PLEHO) -  Allene oxide synthase-lipoxygenase protein from Plexaura homomalla

Seq: 1066 a.a.

Struc: 1002 a.a.*

* PDB and UniProt seqs differ at 2 residue positions (black crosses)

Enzyme reactions

• Enzyme class 2: E.C.1.13.11.40 - arachidonate 8-lipoxygenase.
• Reaction: (5Z,8Z,11Z,14Z)-eicosatetraenoate + O2 = (8R)-hydroperoxy- (5Z,9E,11Z,14Z)-eicosatetraenoate
• Cofactor: Fe cation
• Enzyme class 3: E.C.4.2.1.- - ?????

Note, where more than one E.C. class is given (as above), each may correspond to a different protein domain or, in the case of polyprotein precursors, to a different mature protein.

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

Key reference

Biochemistry 47:10665-10676 (2008)

PubMed id: 18785758

A covalent linker allows for membrane targeting of an oxylipin biosynthetic complex.

N.C.Gilbert, M.Niebuhr, H.Tsuruta, T.Bordelon, O.Ridderbusch, A.Dassey, A.R.Brash, S.G.Bartlett, M.E.Newcomer.

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.