2jev | pdb_00002jev

CRYSTAL STRUCTURE OF HUMAN SPERMINE,SPERMIDINE ACETYLTRANSFERASE IN COMPLEX WITH A BISUBSTRATE ANALOG (N1-ACETYLSPERMINE-S-COA).

spinqualitylabelsall models 2jev, resolution 2.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2jev is a 2 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: NHQ Related: 2b3u, 2b3v, 2b4b, 2b4d, 2b58, 2b5g, 2f5i, 2fxf, 2g3t Activity: Diamine N-acetyltransferase, with EC number 2.3.1.57 Resources: FirstGlance, OCA, RCSB, PDBsum Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The N1-acetylation of spermidine and spermine by spermidine/spermine acetyltransferase (SSAT) is a crucial step in the regulation of the cellular polyamine levels in eukaryotic cells. Altered polyamine levels are associated with a variety of cancers as well as other diseases, and key enzymes in the polyamine pathway, including SSAT, are being explored as potential therapeutic drug targets. We have expressed and purified human SSAT in Escherichia coli and characterized its kinetic and chemical mechanism. Initial velocity and inhibition studies support a random sequential mechanism for the enzyme. The bisubstrate analogue, N1-spermine-acetyl-coenzyme A, exhibited linear, competitive inhibition against both substrates with a true Ki of 6 nM. The pH-activity profile was bell-shaped, depending on the ionization state of two groups exhibiting apparent pKa values of 7.27 and 8.87. The three-dimensional crystal structure of SSAT with bound bisubstrate inhibitor was determined at 2.3 A resolution. The structure of the SSAT-spermine-acetyl-coenzyme A complex suggested that Tyr140 acts as general acid and Glu92, through one or more water molecules, acts as the general base during catalysis. On the basis of kinetic properties, pH dependence, and structural information, we propose an acid/base-assisted reaction catalyzed by SSAT, involving a ternary complex. Mechanistic and structural analysis of human spermidine/spermine N1-acetyltransferase.,Hegde SS, Chandler J, Vetting MW, Yu M, Blanchard JS Biochemistry. 2007 Jun 19;46(24):7187-95. Epub 2007 May 22. PMID:17516632 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Spermidine/spermine N-acetyltransferase

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