2PNC

Crystal Structure of Bovine Plasma Copper-Containing Amine Oxidase in Complex with Clonidine

Summary for 2PNC

• Entry DOI: 10.2210/pdb2pnc/pdb
• Related: 1KSI 1OAC 1TU5
• Related PRD ID: PRD_900017
• Descriptor: Copper amine oxidase, liver isozyme, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, COPPER (II) ION, ... (7 entities in total)
• Functional Keywords: amine oxidase, oxidoreductase, quinoenzyme, tpq, clonidine
• Biological source: Bos taurus (cattle)
• Cellular location: Secreted, extracellular space: Q29437
• Total number of polymer chains: 2
• Total formula weight: 168012.75

Authors

Cendron, L.,Holt, A.,Smith, D.J.,Zanotti, G.,Rigo, A.,Di Paolo, M.L. (deposition date: 2007-04-24, release date: 2008-02-26, Last modification date: 2023-08-30)

Primary citation

Holt, A.,Smith, D.J.,Cendron, L.,Zanotti, G.,Rigo, A.,Di Paolo, M.L.
Multiple binding sites for substrates and modulators of semicarbazide-sensitive amine oxidases: kinetic consequences
Mol.Pharmacol., 73:525-538, 2008

PubMed Abstract: Human semicarbazide-sensitive amine oxidase (SSAO) is a target for novel anti-inflammatory drugs that inhibit enzymatic activity. However, progress in developing such drugs has been hampered by an incomplete understanding of mechanisms involved in substrate turnover. We report here results of a comparative study of human and bovine SSAO enzymes that reveal binding of substrates and other ligands to at least two (human) and up to four (bovine) distinct sites on enzyme monomers. Anaerobic spectroscopy reveals binding of substrates (spermidine and benzylamine) and of an imidazoline site ligand (clonidine) to the reduced active site of bovine SSAO, whereas interactions with oxidized enzyme are evident in kinetic assays and crystallization studies. Radioligand binding experiments with [(3)H]tetraphenylphosphonium, an inhibitor of bovine SSAO that binds to an anionic cavity outside the active site, reveal competition with spermidine, benzylamine, and clonidine, indicating that these ligands also bind to this second anionic region. Kinetic models of bovine SSAO are consistent with one spermidine molecule straddling the active and secondary sites on both oxidized and reduced enzyme, whereas these sites are occupied by two individual molecules of smaller substrates such as benzylamine. Clonidine and other imidazoline site ligands enhance or inhibit activity as a result of differing affinities for both sites on oxidized and reduced enzyme. In contrast, although analyses of kinetic data obtained with human SSAO are also consistent with ligands binding to oxidized and reduced enzyme, we observed no apparent requirement for substrate or modulator binding to any secondary site to model enzyme behavior.

PubMed: 17989349
DOI: 10.1124/mol.107.040964

Experimental method

X-RAY DIFFRACTION (2.4 Å)