2nv1: Difference between revisions

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[[Image:2nv1.gif|left|200px]]<br /><applet load="2nv1" size="~~450~~" color="white" frame="true" align="right" spinBox="true"

[[Image:2nv1.gif|left|200px]]<br /><applet load="2nv1" size="350" color="white" frame="true" align="right" spinBox="true"

caption="2nv1, resolution 2.08Å" />

'''Structure of the synthase subunit Pdx1 (YaaD) of PLP synthase from Bacillus subtilis'''<br />

==Overview==

Vitamin B6 is an essential metabolic cofactor that has more functions in, humans than any other single nutrient. Its de novo biosynthesis occurs, through two mutually exclusive pathways that are absent in animals. The, predominant pathway found in most prokaryotes, fungi, and plants has only, recently been discovered. It is distinguished by a glutamine, amidotransferase, which is remarkable in that it alone can synthesize the, cofactor form, pyridoxal 5'-phosphate (PLP), directly from a triose and a, pentose saccharide and glutamine. Here we report the 3D structure of the, PLP synthase complex with substrate glutamine bound as well as those of, the individual synthase and glutaminase subunits Pdx1 and Pdx2, respectively. The complex is made up of 24 protein units assembled like a, cogwheel, a dodecameric Pdx1 to which 12 Pdx2 subunits attach. In contrast, to the architecture of previously determined glutamine amidotransferases, macromolecular assembly is directed by an N-terminal alpha-helix on the, synthase. Interaction with the synthase subunit leads to glutaminase, activation, resulting in formation of an oxyanion hole, a prerequisite for, catalysis. Mutagenesis permitted identification of the remote glutaminase, and synthase catalytic centers and led us to propose a mechanism whereby, ammonia shuttles between these active sites through a methionine-rich, hydrophobic tunnel.

Vitamin B6 is an essential metabolic cofactor that has more functions in humans than any other single nutrient. Its de novo biosynthesis occurs through two mutually exclusive pathways that are absent in animals. The predominant pathway found in most prokaryotes, fungi, and plants has only recently been discovered. It is distinguished by a glutamine amidotransferase, which is remarkable in that it alone can synthesize the cofactor form, pyridoxal 5'-phosphate (PLP), directly from a triose and a pentose saccharide and glutamine. Here we report the 3D structure of the PLP synthase complex with substrate glutamine bound as well as those of the individual synthase and glutaminase subunits Pdx1 and Pdx2, respectively. The complex is made up of 24 protein units assembled like a cogwheel, a dodecameric Pdx1 to which 12 Pdx2 subunits attach. In contrast to the architecture of previously determined glutamine amidotransferases, macromolecular assembly is directed by an N-terminal alpha-helix on the synthase. Interaction with the synthase subunit leads to glutaminase activation, resulting in formation of an oxyanion hole, a prerequisite for catalysis. Mutagenesis permitted identification of the remote glutaminase and synthase catalytic centers and led us to propose a mechanism whereby ammonia shuttles between these active sites through a methionine-rich hydrophobic tunnel.

==About this Structure==

2NV1 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_subtilis Bacillus subtilis] with CL, MG and EDO as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://~~ispc~~.weizmann.ac.il/oca-bin/ocashort?id=2NV1 OCA].

2NV1 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_subtilis Bacillus subtilis] with <scene name='pdbligand=CL:'>CL</scene>, <scene name='pdbligand=MG:'>MG</scene> and <scene name='pdbligand=EDO:'>EDO</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2NV1 OCA].

==Reference==

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[[Category: synthase]]

''Page seeded by [http://~~ispc~~.weizmann.ac.il/oca OCA ] on ~~Wed Nov~~ 21 12:55:~~43 2007~~''

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 18:11:18 2008''

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@@ Line 1: / Line 1: @@
-[[Image:2nv1.gif|left|200px]]<br /><applet load="2nv1" size="450" color="white" frame="true" align="right" spinBox="true"
+[[Image:2nv1.gif|left|200px]]<br /><applet load="2nv1" size="350" color="white" frame="true" align="right" spinBox="true"
 caption="2nv1, resolution 2.08&Aring;" />
 '''Structure of the synthase subunit Pdx1 (YaaD) of PLP synthase from Bacillus subtilis'''<br />
 ==Overview==
-Vitamin B6 is an essential metabolic cofactor that has more functions in, humans than any other single nutrient. Its de novo biosynthesis occurs, through two mutually exclusive pathways that are absent in animals. The, predominant pathway found in most prokaryotes, fungi, and plants has only, recently been discovered. It is distinguished by a glutamine, amidotransferase, which is remarkable in that it alone can synthesize the, cofactor form, pyridoxal 5'-phosphate (PLP), directly from a triose and a, pentose saccharide and glutamine. Here we report the 3D structure of the, PLP synthase complex with substrate glutamine bound as well as those of, the individual synthase and glutaminase subunits Pdx1 and Pdx2, respectively. The complex is made up of 24 protein units assembled like a, cogwheel, a dodecameric Pdx1 to which 12 Pdx2 subunits attach. In contrast, to the architecture of previously determined glutamine amidotransferases, macromolecular assembly is directed by an N-terminal alpha-helix on the, synthase. Interaction with the synthase subunit leads to glutaminase, activation, resulting in formation of an oxyanion hole, a prerequisite for, catalysis. Mutagenesis permitted identification of the remote glutaminase, and synthase catalytic centers and led us to propose a mechanism whereby, ammonia shuttles between these active sites through a methionine-rich, hydrophobic tunnel.
+Vitamin B6 is an essential metabolic cofactor that has more functions in humans than any other single nutrient. Its de novo biosynthesis occurs through two mutually exclusive pathways that are absent in animals. The predominant pathway found in most prokaryotes, fungi, and plants has only recently been discovered. It is distinguished by a glutamine amidotransferase, which is remarkable in that it alone can synthesize the cofactor form, pyridoxal 5'-phosphate (PLP), directly from a triose and a pentose saccharide and glutamine. Here we report the 3D structure of the PLP synthase complex with substrate glutamine bound as well as those of the individual synthase and glutaminase subunits Pdx1 and Pdx2, respectively. The complex is made up of 24 protein units assembled like a cogwheel, a dodecameric Pdx1 to which 12 Pdx2 subunits attach. In contrast to the architecture of previously determined glutamine amidotransferases, macromolecular assembly is directed by an N-terminal alpha-helix on the synthase. Interaction with the synthase subunit leads to glutaminase activation, resulting in formation of an oxyanion hole, a prerequisite for catalysis. Mutagenesis permitted identification of the remote glutaminase and synthase catalytic centers and led us to propose a mechanism whereby ammonia shuttles between these active sites through a methionine-rich hydrophobic tunnel.
 ==About this Structure==
-NV1 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_subtilis Bacillus subtilis] with CL, MG and EDO as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2NV1 OCA].
+NV1 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_subtilis Bacillus subtilis] with <scene name='pdbligand=CL:'>CL</scene>, <scene name='pdbligand=MG:'>MG</scene> and <scene name='pdbligand=EDO:'>EDO</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2NV1 OCA].
 ==Reference==
@@ Line 22: / Line 22: @@
 [[Category: synthase]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 12:55:43 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 18:11:18 2008''