1pvw
From Proteopedia
(New page: 200px<br /><applet load="1pvw" size="450" color="white" frame="true" align="right" spinBox="true" caption="1pvw, resolution 2.45Å" /> '''3,4-dihydroxy-2-buta...) |
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| - | [[Image:1pvw.jpg|left|200px]]<br /><applet load="1pvw" size=" | + | [[Image:1pvw.jpg|left|200px]]<br /><applet load="1pvw" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1pvw, resolution 2.45Å" /> | caption="1pvw, resolution 2.45Å" /> | ||
'''3,4-dihydroxy-2-butanone 4-phosphate synthase from M. jannaschii'''<br /> | '''3,4-dihydroxy-2-butanone 4-phosphate synthase from M. jannaschii'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Skeletal rearrangements of carbohydrates are crucial for many biosynthetic | + | Skeletal rearrangements of carbohydrates are crucial for many biosynthetic pathways. In riboflavin biosynthesis ribulose 5-phosphate is converted into 3,4-dihydroxy-2-butanone 4-phosphate while its C4 atom is released as formate in a sequence of metal-dependent reactions. Here, we present the crystal structure of Methanococcus jannaschii 3,4-dihydroxy-2-butanone 4-phosphate synthase in complex with the substrate ribulose 5-phosphate at a dimetal center presumably consisting of non-catalytic zinc and calcium ions at 1.7-A resolution. The carbonyl group (O2) and two out of three free hydroxyl groups (OH3 and OH4) of the substrate are metal-coordinated. We correlate previous mutational studies on this enzyme with the present structural results. Residues of the first coordination sphere involved in metal binding are indispensable for catalytic activity. Only Glu-185 of the second coordination sphere cannot be replaced without complete loss of activity. It contacts the C3 hydrogen atom directly and probably initiates enediol formation in concert with both metal ions to start the reaction sequence. Mechanistic similarities to Rubisco acting on the similar substrate ribulose 1,5-diphosphate in carbon dioxide fixation as well as other carbohydrate (reducto-) isomerases are discussed. |
==About this Structure== | ==About this Structure== | ||
| - | 1PVW is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Methanocaldococcus_jannaschii Methanocaldococcus jannaschii] with ZN, CA and PO4 as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1PVW is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Methanocaldococcus_jannaschii Methanocaldococcus jannaschii] with <scene name='pdbligand=ZN:'>ZN</scene>, <scene name='pdbligand=CA:'>CA</scene> and <scene name='pdbligand=PO4:'>PO4</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1PVW OCA]. |
==Reference== | ==Reference== | ||
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[[Category: riboflavin biosynthesis]] | [[Category: riboflavin biosynthesis]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:33:04 2008'' |
Revision as of 12:33, 21 February 2008
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3,4-dihydroxy-2-butanone 4-phosphate synthase from M. jannaschii
Overview
Skeletal rearrangements of carbohydrates are crucial for many biosynthetic pathways. In riboflavin biosynthesis ribulose 5-phosphate is converted into 3,4-dihydroxy-2-butanone 4-phosphate while its C4 atom is released as formate in a sequence of metal-dependent reactions. Here, we present the crystal structure of Methanococcus jannaschii 3,4-dihydroxy-2-butanone 4-phosphate synthase in complex with the substrate ribulose 5-phosphate at a dimetal center presumably consisting of non-catalytic zinc and calcium ions at 1.7-A resolution. The carbonyl group (O2) and two out of three free hydroxyl groups (OH3 and OH4) of the substrate are metal-coordinated. We correlate previous mutational studies on this enzyme with the present structural results. Residues of the first coordination sphere involved in metal binding are indispensable for catalytic activity. Only Glu-185 of the second coordination sphere cannot be replaced without complete loss of activity. It contacts the C3 hydrogen atom directly and probably initiates enediol formation in concert with both metal ions to start the reaction sequence. Mechanistic similarities to Rubisco acting on the similar substrate ribulose 1,5-diphosphate in carbon dioxide fixation as well as other carbohydrate (reducto-) isomerases are discussed.
About this Structure
1PVW is a Single protein structure of sequence from Methanocaldococcus jannaschii with , and as ligands. Full crystallographic information is available from OCA.
Reference
Structure of 3,4-dihydroxy-2-butanone 4-phosphate synthase from Methanococcus jannaschii in complex with divalent metal ions and the substrate ribulose 5-phosphate: implications for the catalytic mechanism., Steinbacher S, Schiffmann S, Richter G, Huber R, Bacher A, Fischer M, J Biol Chem. 2003 Oct 24;278(43):42256-65. Epub 2003 Aug 6. PMID:12904291
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