1ff9
From Proteopedia
(New page: 200px<br /><applet load="1ff9" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ff9, resolution 2.00Å" /> '''APO SACCHAROPINE RED...) |
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| - | [[Image:1ff9.jpg|left|200px]]<br /><applet load="1ff9" size=" | + | [[Image:1ff9.jpg|left|200px]]<br /><applet load="1ff9" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1ff9, resolution 2.00Å" /> | caption="1ff9, resolution 2.00Å" /> | ||
'''APO SACCHAROPINE REDUCTASE'''<br /> | '''APO SACCHAROPINE REDUCTASE'''<br /> | ||
==Overview== | ==Overview== | ||
| - | BACKGROUND: The biosynthesis of the essential amino acid lysine in higher | + | BACKGROUND: The biosynthesis of the essential amino acid lysine in higher fungi and cyanobacteria occurs via the alpha-aminoadipate pathway, which is completely different from the lysine biosynthetic pathway found in plants and bacteria. The penultimate reaction in the alpha-aminoadipate pathway is catalysed by NADPH-dependent saccharopine reductase. We set out to determine the structure of this enzyme as a first step in exploring the structural biology of fungal lysine biosynthesis. RESULTS: We have determined the three-dimensional structure of saccharopine reductase from the plant pathogen Magnaporthe grisea in its apo form to 2.0 A resolution and as a ternary complex with NADPH and saccharopine to 2.1 A resolution. Saccharopine reductase is a homodimer, and each subunit consists of three domains, which are not consecutive in amino acid sequence. Domain I contains a variant of the Rossmann fold that binds NADPH. Domain II folds into a mixed seven-stranded beta sheet flanked by alpha helices and is involved in substrate binding and dimer formation. Domain III is all-helical. The structure analysis of the ternary complex reveals a large movement of domain III upon ligand binding. The active site is positioned in a cleft between the NADPH-binding domain and the second alpha/beta domain. Saccharopine is tightly bound to the enzyme via a number of hydrogen bonds to invariant amino acid residues. CONCLUSIONS: On the basis of the structure of the ternary complex of saccharopine reductase, an enzymatic mechanism is proposed that includes the formation of a Schiff base as a key intermediate. Despite the lack of overall sequence homology, the fold of saccharopine reductase is similar to that observed in some enzymes of the diaminopimelate pathway of lysine biosynthesis in bacteria. These structural similarities suggest an evolutionary relationship between two different major families of amino acid biosynthetic pathway, the glutamate and aspartate families. |
==About this Structure== | ==About this Structure== | ||
| - | 1FF9 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Magnaporthe_grisea Magnaporthe grisea] with SO4 as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Saccharopine_dehydrogenase_(NAD(+),_L-lysine-forming) Saccharopine dehydrogenase (NAD(+), L-lysine-forming)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.5.1.7 1.5.1.7] Full crystallographic information is available from [http:// | + | 1FF9 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Magnaporthe_grisea Magnaporthe grisea] with <scene name='pdbligand=SO4:'>SO4</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Saccharopine_dehydrogenase_(NAD(+),_L-lysine-forming) Saccharopine dehydrogenase (NAD(+), L-lysine-forming)], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.5.1.7 1.5.1.7] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1FF9 OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Lindqvist, Y.]] | [[Category: Lindqvist, Y.]] | ||
[[Category: Schneider, G.]] | [[Category: Schneider, G.]] | ||
| - | [[Category: Steffens, J | + | [[Category: Steffens, J J.]] |
[[Category: SO4]] | [[Category: SO4]] | ||
[[Category: alpha-aminoadipate pathway]] | [[Category: alpha-aminoadipate pathway]] | ||
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[[Category: saccharopine reductase]] | [[Category: saccharopine reductase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:38:05 2008'' |
Revision as of 10:38, 21 February 2008
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APO SACCHAROPINE REDUCTASE
Overview
BACKGROUND: The biosynthesis of the essential amino acid lysine in higher fungi and cyanobacteria occurs via the alpha-aminoadipate pathway, which is completely different from the lysine biosynthetic pathway found in plants and bacteria. The penultimate reaction in the alpha-aminoadipate pathway is catalysed by NADPH-dependent saccharopine reductase. We set out to determine the structure of this enzyme as a first step in exploring the structural biology of fungal lysine biosynthesis. RESULTS: We have determined the three-dimensional structure of saccharopine reductase from the plant pathogen Magnaporthe grisea in its apo form to 2.0 A resolution and as a ternary complex with NADPH and saccharopine to 2.1 A resolution. Saccharopine reductase is a homodimer, and each subunit consists of three domains, which are not consecutive in amino acid sequence. Domain I contains a variant of the Rossmann fold that binds NADPH. Domain II folds into a mixed seven-stranded beta sheet flanked by alpha helices and is involved in substrate binding and dimer formation. Domain III is all-helical. The structure analysis of the ternary complex reveals a large movement of domain III upon ligand binding. The active site is positioned in a cleft between the NADPH-binding domain and the second alpha/beta domain. Saccharopine is tightly bound to the enzyme via a number of hydrogen bonds to invariant amino acid residues. CONCLUSIONS: On the basis of the structure of the ternary complex of saccharopine reductase, an enzymatic mechanism is proposed that includes the formation of a Schiff base as a key intermediate. Despite the lack of overall sequence homology, the fold of saccharopine reductase is similar to that observed in some enzymes of the diaminopimelate pathway of lysine biosynthesis in bacteria. These structural similarities suggest an evolutionary relationship between two different major families of amino acid biosynthetic pathway, the glutamate and aspartate families.
About this Structure
1FF9 is a Single protein structure of sequence from Magnaporthe grisea with as ligand. Active as Saccharopine dehydrogenase (NAD(+), L-lysine-forming), with EC number 1.5.1.7 Full crystallographic information is available from OCA.
Reference
Crystal structure of saccharopine reductase from Magnaporthe grisea, an enzyme of the alpha-aminoadipate pathway of lysine biosynthesis., Johansson E, Steffens JJ, Lindqvist Y, Schneider G, Structure. 2000 Oct 15;8(10):1037-47. PMID:11080625
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