1w1q
From Proteopedia
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'''PLANT CYTOKININ DEHYDROGENASE IN COMPLEX WITH ISOPENTENYLADENINE''' | '''PLANT CYTOKININ DEHYDROGENASE IN COMPLEX WITH ISOPENTENYLADENINE''' | ||
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[[Category: Malito, E.]] | [[Category: Malito, E.]] | ||
[[Category: Mattevi, A.]] | [[Category: Mattevi, A.]] | ||
| - | [[Category: | + | [[Category: Cytokinin]] |
| - | [[Category: | + | [[Category: Fad]] |
| - | [[Category: | + | [[Category: Flavin]] |
| - | [[Category: | + | [[Category: Flavoprotein]] |
| - | [[Category: | + | [[Category: Oxidoreductase]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 13:01:50 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 10:01, 3 May 2008
PLANT CYTOKININ DEHYDROGENASE IN COMPLEX WITH ISOPENTENYLADENINE
Overview
Cytokinins form a diverse class of compounds that are essential for plant growth. Cytokinin dehydrogenase has a major role in the control of the levels of these plant hormones by catalysing their irreversible oxidation. The crystal structure of Zea mays cytokinin dehydrogenase displays the same two-domain topology of the flavoenzymes of the vanillyl-alcohol oxidase family but its active site cannot be related to that of any other family member. The X-ray analysis reveals a bipartite architecture of the catalytic centre, which consists of a funnel-shaped region on the protein surface and an internal cavity lined by the flavin ring. A pore with diameter of about 4A connects the two active-site regions. Snapshots of two critical steps along the reaction cycle were obtained through the structural analysis of the complexes with a slowly reacting substrate and the reaction product, which correspond to the states immediately before (Michaelis complex) and after (product complex) oxidation has taken place. The substrate displays a "plug-into-socket" binding mode that seals the catalytic site and precisely positions the carbon atom undergoing oxidation in close contact with the reactive locus of the flavin. A polarising H-bond between the substrate amine group and an Asp-Glu pair may facilitate oxidation. Substrate to product conversion results in small atomic movements, which lead to a planar conformation of the reaction product allowing double-bond conjugation. These features in the mechanism of amine recognition and oxidation differ from those observed in other flavin-dependent amine oxidases.
About this Structure
1W1Q is a Single protein structure of sequence from Zea mays. Full crystallographic information is available from OCA.
Reference
Structures of Michaelis and product complexes of plant cytokinin dehydrogenase: implications for flavoenzyme catalysis., Malito E, Coda A, Bilyeu KD, Fraaije MW, Mattevi A, J Mol Biol. 2004 Aug 27;341(5):1237-49. PMID:15321719 Page seeded by OCA on Sat May 3 13:01:50 2008
