1dxm: Difference between revisions
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==Overview== | ==Overview== | ||
The glycine decarboxylase complex consists of four different component, enzymes (P-, H-, T- and L-proteins). The 14-kDa lipoamide-containing, H-protein plays a pivotal role in the complete sequence of reactions as, its prosthetic group (lipoic acid) interacts successively with the three, other components of the complex and undergoes a cycle of reductive, methylamination, methylamine transfer and electron transfer. With the aim, to understand the interaction between the H-protein and its different, partners, we have previously determined the crystal structure of the, oxidized and methylaminated forms of the H-protein. In the present study, we have crystallized the H-protein in its reduced state and the L-protein, (lipoamide dehydrogenase or dihydrolipoamide dehydrogenase). The L-protein, ... [ | The glycine decarboxylase complex consists of four different component, enzymes (P-, H-, T- and L-proteins). The 14-kDa lipoamide-containing, H-protein plays a pivotal role in the complete sequence of reactions as, its prosthetic group (lipoic acid) interacts successively with the three, other components of the complex and undergoes a cycle of reductive, methylamination, methylamine transfer and electron transfer. With the aim, to understand the interaction between the H-protein and its different, partners, we have previously determined the crystal structure of the, oxidized and methylaminated forms of the H-protein. In the present study, we have crystallized the H-protein in its reduced state and the L-protein, (lipoamide dehydrogenase or dihydrolipoamide dehydrogenase). The L-protein, has been overexpressed in Escherichia coli and refolded from inclusion, bodies in an active form. Crystals were obtained from the refolded, L-protein and the structure has been determined by X-ray crystallography., This first crystal structure of a plant dihydrolipoamide dehydrogenase is, similar to other known dihydrolipoamide dehydrogenase structures. The, crystal structure of the H-protein in its reduced form has been determined, and compared to the structure of the other forms of the protein. It is, isomorphous to the structure of the oxidized form. In contrast with, methylaminated H-protein where the loaded lipoamide arm was locked into a, cavity of the protein, the reduced lipoamide arm appeared freely exposed, to the solvent. Such a freedom is required to allow its targeting inside, the hollow active site of L-protein. Our results strongly suggest that a, direct interaction between the H- and L-proteins is not necessary for the, reoxidation of the reduced lipoamide arm bound to the H-protein. This, hypothesis is supported by biochemical data [Neuburger, M., Polidori, A.M., Pietre, E., Faure, M., Jourdain, A., Bourguignon, J., Pucci, B. &, Douce, R. (2000) Eur. J. Biochem. 267, 2882-2889] and by small angle X-ray, scattering experiments reported herein. | ||
==About this Structure== | ==About this Structure== | ||
1DXM is a | 1DXM is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pisum_sativum Pisum sativum] with RED as [http://en.wikipedia.org/wiki/ligand ligand]. Structure known Active Sites: LP1 and LP2. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1DXM OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: mitochondria]] | [[Category: mitochondria]] | ||
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 14:02:29 2007'' | ||
Revision as of 14:57, 5 November 2007
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REDUCED FORM OF THE H PROTEIN FROM GLYCINE DECARBOXYLASE COMPLEX
OverviewOverview
The glycine decarboxylase complex consists of four different component, enzymes (P-, H-, T- and L-proteins). The 14-kDa lipoamide-containing, H-protein plays a pivotal role in the complete sequence of reactions as, its prosthetic group (lipoic acid) interacts successively with the three, other components of the complex and undergoes a cycle of reductive, methylamination, methylamine transfer and electron transfer. With the aim, to understand the interaction between the H-protein and its different, partners, we have previously determined the crystal structure of the, oxidized and methylaminated forms of the H-protein. In the present study, we have crystallized the H-protein in its reduced state and the L-protein, (lipoamide dehydrogenase or dihydrolipoamide dehydrogenase). The L-protein, has been overexpressed in Escherichia coli and refolded from inclusion, bodies in an active form. Crystals were obtained from the refolded, L-protein and the structure has been determined by X-ray crystallography., This first crystal structure of a plant dihydrolipoamide dehydrogenase is, similar to other known dihydrolipoamide dehydrogenase structures. The, crystal structure of the H-protein in its reduced form has been determined, and compared to the structure of the other forms of the protein. It is, isomorphous to the structure of the oxidized form. In contrast with, methylaminated H-protein where the loaded lipoamide arm was locked into a, cavity of the protein, the reduced lipoamide arm appeared freely exposed, to the solvent. Such a freedom is required to allow its targeting inside, the hollow active site of L-protein. Our results strongly suggest that a, direct interaction between the H- and L-proteins is not necessary for the, reoxidation of the reduced lipoamide arm bound to the H-protein. This, hypothesis is supported by biochemical data [Neuburger, M., Polidori, A.M., Pietre, E., Faure, M., Jourdain, A., Bourguignon, J., Pucci, B. &, Douce, R. (2000) Eur. J. Biochem. 267, 2882-2889] and by small angle X-ray, scattering experiments reported herein.
About this StructureAbout this Structure
1DXM is a Single protein structure of sequence from Pisum sativum with RED as ligand. Structure known Active Sites: LP1 and LP2. Full crystallographic information is available from OCA.
ReferenceReference
Interaction between the lipoamide-containing H-protein and the lipoamide dehydrogenase (L-protein) of the glycine decarboxylase multienzyme system 2. Crystal structures of H- and L-proteins., Faure M, Bourguignon J, Neuburger M, MacHerel D, Sieker L, Ober R, Kahn R, Cohen-Addad C, Douce R, Eur J Biochem. 2000 May;267(10):2890-8. PMID:10806386
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