PDBsum entry 5jw1

Oxidoreductase

PDB id: 5jw1

Contents

Protein chains

552 a.a.

Ligands

NAG-NAG ×2

COH ×2

CEL ×2

BOG

NAG ×4

Waters ×15

PDB id:

5jw1

Name:

Oxidoreductase

Title:

Crystal structure of celecoxib bound to s121p murine cox-2 mutant

Structure:

Prostaglandin g/h synthase 2. Chain: a, b. Synonym: cyclooxygenase-2,cox-2,glucocorticoid-regulated inflammatory cyclooxygenase,gripghs,macrophage activation-associated marker protein p71/73,pes-2,phs ii,prostaglandin h2 synthase 2,pghs-2, prostaglandin-endoperoxide synthase 2,tis10 protein. Engineered: yes. Mutation: yes

Source:

Mus musculus. Mouse. Organism_taxid: 10090. Gene: ptgs2, cox-2, cox2, pghs-b, tis10. Expressed in: spodoptera frugiperda. Expression_system_taxid: 7108

Resolution:

2.82Å R-factor: 0.191 R-free: 0.226

Authors:

M.G.Malkowski,B.J.Orlando

Key ref:

L.Dong et al. (2016). Fatty Acid Binding to the Allosteric Subunit of Cyclooxygenase-2 Relieves a Tonic Inhibition of the Catalytic Subunit. J Biol Chem, 291, 25641-25655. PubMed id: 27756840 DOI: 10.1074/jbc.M116.757310

Date:

11-May-16 Release date: 26-Oct-16

Protein chains

Q05769  (PGH2_MOUSE) -  Prostaglandin G/H synthase 2 from Mus musculus

Seq: 604 a.a.

Struc: 552 a.a.*

* PDB and UniProt seqs differ at 3 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.1.14.99.1 - prostaglandin-endoperoxide synthase.
• Reaction: (5Z,8Z,11Z,14Z)-eicosatetraenoate + AH2 + 2 O2 = prostaglandin H2 + A + H2O

(5Z,8Z,11Z,14Z)-eicosatetraenoate + AH2 + 2 × O2 = prostaglandin H2 + + H2O (Bound ligand (Het Group name = COH) matches with 51.11% similarity)

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

Added reference

DOI no: 10.1074/jbc.M116.757310

J Biol Chem 291:25641-25655 (2016)

PubMed id: 27756840

Fatty Acid Binding to the Allosteric Subunit of Cyclooxygenase-2 Relieves a Tonic Inhibition of the Catalytic Subunit.

L.Dong, C.Yuan, B.J.Orlando, M.G.Malkowski, W.L.Smith.

ABSTRACT

Prostaglandin endoperoxide H synthase-2 (PGHS-2), also called cyclooxygenase-2 (COX-2), converts arachidonic acid to PGH₂ PGHS-2 is a conformational heterodimer composed of allosteric (E_allo) and catalytic (E_cat) subunits. Fatty acids (FAs) bind to Arg-120 of E_allo increasing to different degrees, depending on the FA, the V_max of its E_cat partner. We report here that movement of helical residues 120-122 and loop residues 123-129 of E_allo underlies the allosteric effects of FAs and allosteric COX-2 inhibitors, including naproxen and flurbiprofen. An S121P substitution in both PGHS-2 monomers yields a variant (S121P/S121P PGHS-2) that has 1.7-1.8 times the V_max of native PGHS-2 and is relatively insensitive to activation by FAs or inhibition by allosteric inhibitors. The S121P substitution in E_allo is primarily responsible for these effects. In X-ray crystal structures, the Cα atoms of helical residues 119-122 of S121P/S121P PGHS-2 are displaced from their normal positions. Additionally, the S121P/S121P PGHS-2 variants in which Pro-127 and Ser-541 are replaced by cysteines spontaneously forms Cys-127 to Cys-541 cross-links between monomers. This is unlike the corresponding native PGHS-2 variant and suggests that S121P substitutions also unhinge the loop involving residues 123-129. We conclude the following: (a) the region involving residues 120-129 of unoccupied E_allo tonically inhibits E_cat; (b) binding of an activating FA (e.g. arachidonic, palmitic, or oleic acid) to E_allo or an S121P substitution in E_allo repositions this region to increase E_cat activity; and (c) allosteric COX inhibitors act by preventing FA binding to E_allo and additionally by relocating E_allo residues to inhibit E_cat.