1kuv
From Proteopedia
(New page: 200px<br /><applet load="1kuv" size="450" color="white" frame="true" align="right" spinBox="true" caption="1kuv, resolution 2.0Å" /> '''X-ray Crystallographi...) |
|||
| Line 1: | Line 1: | ||
| - | [[Image:1kuv.jpg|left|200px]]<br /><applet load="1kuv" size=" | + | [[Image:1kuv.jpg|left|200px]]<br /><applet load="1kuv" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1kuv, resolution 2.0Å" /> | caption="1kuv, resolution 2.0Å" /> | ||
'''X-ray Crystallographic Studies of Serotonin N-acetyltransferase Catalysis and Inhibition'''<br /> | '''X-ray Crystallographic Studies of Serotonin N-acetyltransferase Catalysis and Inhibition'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The structure of serotonin N-acetyltransferase (also known as | + | The structure of serotonin N-acetyltransferase (also known as arylalkylamine N-acetyltransferase; AANAT) bound to a potent bisubstrate analog inhibitor has been determined at 2.0 A resolution using a two-edge (Se, Br) multiwavelength anomalous diffraction (MAD) experiment. This acetyl-CoA dependent enzyme is a member of the GCN5-related family of N-acetyltransferases (GNATs), which share four conserved sequence motifs (A-D). In serotonin N-acetyltransferase, motif A adopts an alpha/beta conformation characteristic of the phylogenetically invariant cofactor binding site seen in all previously characterized GNATs. Motif B displays a significantly lower level of conservation among family members, giving rise to a novel alpha/beta structure for the serotonin binding slot. Utilization of a brominated CoA-S-acetyl-tryptamine-bisubstrate analog inhibitor and the MAD method permitted conclusive identification of two radically different conformations for the tryptamine moiety in the catalytic site (cis and trans). A second high-resolution X-ray structure of the enzyme bound to a bisubstrate analog inhibitor, with a longer tether between the acetyl-CoA and tryptamine moieties, demonstrates only the trans conformation. Given a previous proposal that AANAT can catalyze an alkyltransferase reaction in a conformationally altered active site relative to its acetyltransferase activity, it is possible that the two conformations of the bisubstrate analog observed crystallographically correspond to these alternative reaction pathways. Our findings may ultimately lead to the design of analogs with improved AANAT inhibitory properties for in vivo applications. |
==About this Structure== | ==About this Structure== | ||
| - | 1KUV is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Ovis_aries Ovis aries] with MG and CA5 as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Aralkylamine_N-acetyltransferase Aralkylamine N-acetyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.3.1.87 2.3.1.87] Full crystallographic information is available from [http:// | + | 1KUV is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Ovis_aries Ovis aries] with <scene name='pdbligand=MG:'>MG</scene> and <scene name='pdbligand=CA5:'>CA5</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Aralkylamine_N-acetyltransferase Aralkylamine N-acetyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.3.1.87 2.3.1.87] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1KUV OCA]. |
==Reference== | ==Reference== | ||
| Line 14: | Line 14: | ||
[[Category: Ovis aries]] | [[Category: Ovis aries]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Angelis, J | + | [[Category: Angelis, J De.]] |
| - | [[Category: Burley, S | + | [[Category: Burley, S K.]] |
| - | [[Category: Cole, P | + | [[Category: Cole, P A.]] |
| - | [[Category: Khalil, E | + | [[Category: Khalil, E M.]] |
[[Category: Wolf, E.]] | [[Category: Wolf, E.]] | ||
[[Category: CA5]] | [[Category: CA5]] | ||
| Line 25: | Line 25: | ||
[[Category: enzyme-inhibitor complex]] | [[Category: enzyme-inhibitor complex]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:38:12 2008'' |
Revision as of 11:38, 21 February 2008
|
X-ray Crystallographic Studies of Serotonin N-acetyltransferase Catalysis and Inhibition
Overview
The structure of serotonin N-acetyltransferase (also known as arylalkylamine N-acetyltransferase; AANAT) bound to a potent bisubstrate analog inhibitor has been determined at 2.0 A resolution using a two-edge (Se, Br) multiwavelength anomalous diffraction (MAD) experiment. This acetyl-CoA dependent enzyme is a member of the GCN5-related family of N-acetyltransferases (GNATs), which share four conserved sequence motifs (A-D). In serotonin N-acetyltransferase, motif A adopts an alpha/beta conformation characteristic of the phylogenetically invariant cofactor binding site seen in all previously characterized GNATs. Motif B displays a significantly lower level of conservation among family members, giving rise to a novel alpha/beta structure for the serotonin binding slot. Utilization of a brominated CoA-S-acetyl-tryptamine-bisubstrate analog inhibitor and the MAD method permitted conclusive identification of two radically different conformations for the tryptamine moiety in the catalytic site (cis and trans). A second high-resolution X-ray structure of the enzyme bound to a bisubstrate analog inhibitor, with a longer tether between the acetyl-CoA and tryptamine moieties, demonstrates only the trans conformation. Given a previous proposal that AANAT can catalyze an alkyltransferase reaction in a conformationally altered active site relative to its acetyltransferase activity, it is possible that the two conformations of the bisubstrate analog observed crystallographically correspond to these alternative reaction pathways. Our findings may ultimately lead to the design of analogs with improved AANAT inhibitory properties for in vivo applications.
About this Structure
1KUV is a Single protein structure of sequence from Ovis aries with and as ligands. Active as Aralkylamine N-acetyltransferase, with EC number 2.3.1.87 Full crystallographic information is available from OCA.
Reference
X-ray crystallographic studies of serotonin N-acetyltransferase catalysis and inhibition., Wolf E, De Angelis J, Khalil EM, Cole PA, Burley SK, J Mol Biol. 2002 Mar 22;317(2):215-24. PMID:11902838
Page seeded by OCA on Thu Feb 21 13:38:12 2008
