5F19

The Crystal Structure of Aspirin Acetylated Human Cyclooxygenase-2

Summary for 5F19

• Entry DOI: 10.2210/pdb5f19/pdb
• Related: 5F1A
• Descriptor: Prostaglandin G/H synthase 2, alpha-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, ... (9 entities in total)
• Functional Keywords: membrane protein, cyclooxygenase, cyxlooxygenase-2, monotopic, aspirin, complex, covalent inhibitor, oxidoreductase-inhibitor complex, oxidoreductase/inhibitor
• Biological source: Homo sapiens (Human)
• Total number of polymer chains: 2
• Total formula weight: 132205.01

Authors

Lucido, M.J.,Orlando, B.J.,Malkowski, M.G. (deposition date: 2015-11-30, release date: 2016-03-16, Last modification date: 2024-11-20)

Primary citation

Lucido, M.J.,Orlando, B.J.,Vecchio, A.J.,Malkowski, M.G.
Crystal Structure of Aspirin-Acetylated Human Cyclooxygenase-2: Insight into the Formation of Products with Reversed Stereochemistry.
Biochemistry, 55:1226-1238, 2016

PubMed Abstract: Aspirin and other nonsteroidal anti-inflammatory drugs target the cyclooxygenase enzymes (COX-1 and COX-2) to block the formation of prostaglandins. Aspirin is unique in that it covalently modifies each enzyme by acetylating Ser-530 within the cyclooxygenase active site. Acetylation of COX-1 leads to complete loss of activity, while acetylation of COX-2 results in the generation of the monooxygenated product 15(R)-hydroxyeicosatetraenoic acid (15R-HETE). Ser-530 has also been shown to influence the stereochemistry for the addition of oxygen to the prostaglandin product. We determined the crystal structures of S530T murine (mu) COX-2, aspirin-acetylated human (hu) COX-2, and huCOX-2 in complex with salicylate to 1.9, 2.0, and 2.4 Å, respectively. The structures reveal that (1) the acetylated Ser-530 completely blocks access to the hydrophobic groove, (2) the observed binding pose of salicylate is reflective of the enzyme-inhibitor complex prior to acetylation, and (3) the observed Thr-530 rotamer in the S530T muCOX-2 crystal structure does not impede access to the hydrophobic groove. On the basis of these structural observations, along with functional analysis of the S530T/G533V double mutant, we propose a working hypothesis for the generation of 15R-HETE by aspirin-acetylated COX-2. We also observe differential acetylation of COX-2 purified in various detergent systems and nanodiscs, indicating that detergent and lipid binding within the membrane-binding domain of the enzyme alters the rate of the acetylation reaction in vitro.

PubMed: 26859324
DOI: 10.1021/acs.biochem.5b01378

Experimental method

X-RAY DIFFRACTION (2.04 Å)