1t3d: Difference between revisions

Revision as of 16:09, 21 February 2008

Crystal structure of Serine Acetyltransferase from E.coli at 2.2A

OverviewOverview

Serine acetyltransferase (SAT) catalyzes the first step of cysteine synthesis in microorganisms and higher plants. Here we present the 2.2 A crystal structure of SAT from Escherichia coli, which is a dimer of trimers, in complex with cysteine. The SAT monomer consists of an amino-terminal alpha-helical domain and a carboxyl-terminal left-handed beta-helix. We identify His(158) and Asp(143) as essential residues that form a catalytic triad with the substrate for acetyl transfer. This structure shows the mechanism by which cysteine inhibits SAT activity and thus controls its own synthesis. Cysteine is found to bind at the serine substrate site and not the acetyl-CoA site that had been reported previously. On the basis of the geometry around the cysteine binding site, we are able to suggest a mechanism for the O-acetylation of serine by SAT. We also compare the structure of SAT with other left-handed beta-helical structures.

About this StructureAbout this Structure

1T3D is a Single protein structure of sequence from Escherichia coli with as ligand. Active as Serine O-acetyltransferase, with EC number 2.3.1.30 Full crystallographic information is available from OCA.

ReferenceReference

The structure and mechanism of serine acetyltransferase from Escherichia coli., Pye VE, Tingey AP, Robson RL, Moody PC, J Biol Chem. 2004 Sep 24;279(39):40729-36. Epub 2004 Jul 1. PMID:15231846

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-[[Image:1t3d.jpg|left|200px]]<br /><applet load="1t3d" size="450" color="white" frame="true" align="right" spinBox="true"
+[[Image:1t3d.jpg|left|200px]]<br /><applet load="1t3d" size="350" color="white" frame="true" align="right" spinBox="true"
 caption="1t3d, resolution 2.20&Aring;" />
 '''Crystal structure of Serine Acetyltransferase from E.coli at 2.2A'''<br />
 ==Overview==
-Serine acetyltransferase (SAT) catalyzes the first step of cysteine, synthesis in microorganisms and higher plants. Here we present the 2.2 A, crystal structure of SAT from Escherichia coli, which is a dimer of, trimers, in complex with cysteine. The SAT monomer consists of an, amino-terminal alpha-helical domain and a carboxyl-terminal left-handed, beta-helix. We identify His(158) and Asp(143) as essential residues that, form a catalytic triad with the substrate for acetyl transfer. This, structure shows the mechanism by which cysteine inhibits SAT activity and, thus controls its own synthesis. Cysteine is found to bind at the serine, substrate site and not the acetyl-CoA site that had been reported, previously. On the basis of the geometry around the cysteine binding site, we are able to suggest a mechanism for the O-acetylation of serine by SAT., We also compare the structure of SAT with other left-handed beta-helical, structures.
+Serine acetyltransferase (SAT) catalyzes the first step of cysteine synthesis in microorganisms and higher plants. Here we present the 2.2 A crystal structure of SAT from Escherichia coli, which is a dimer of trimers, in complex with cysteine. The SAT monomer consists of an amino-terminal alpha-helical domain and a carboxyl-terminal left-handed beta-helix. We identify His(158) and Asp(143) as essential residues that form a catalytic triad with the substrate for acetyl transfer. This structure shows the mechanism by which cysteine inhibits SAT activity and thus controls its own synthesis. Cysteine is found to bind at the serine substrate site and not the acetyl-CoA site that had been reported previously. On the basis of the geometry around the cysteine binding site, we are able to suggest a mechanism for the O-acetylation of serine by SAT. We also compare the structure of SAT with other left-handed beta-helical structures.
 ==About this Structure==
-T3D is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with CYS as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Serine_O-acetyltransferase Serine O-acetyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.3.1.30 2.3.1.30] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1T3D OCA].
+T3D is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli] with <scene name='pdbligand=CYS:'>CYS</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Serine_O-acetyltransferase Serine O-acetyltransferase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.3.1.30 2.3.1.30] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1T3D OCA].
 ==Reference==
@@ Line 14: / Line 14: @@
 [[Category: Serine O-acetyltransferase]]
 [[Category: Single protein]]
-[[Category: Moody, P.C.]]
+[[Category: Moody, P C.]]
-[[Category: Pye, V.E.]]
+[[Category: Pye, V E.]]
-[[Category: Robson, R.L.]]
+[[Category: Robson, R L.]]
-[[Category: Tingey, A.P.]]
+[[Category: Tingey, A P.]]
 [[Category: CYS]]
 [[Category: dimer of trimers]]
 [[Category: left-handed-beta-helix]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 02:57:19 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:09:28 2008''