2std
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SCYTALONE DEHYDRATASE COMPLEXED WITH TIGHT-BINDING INHIBITOR CARPROPAMID
Overview
Scytalone dehydratase is a member of the group of enzymes involved in fungal melanin biosynthesis in a phytopathogenic fungus, Pyricularia oryzae, which causes rice blast disease. Carpropamid [(1RS,3SR)-2, 2-dichloro-N-[(R)-1-(4-chlorophenyl)ethyl]-1-ethyl-3-methylcyclopropa necarboxamide] is a tight-binding inhibitor of the enzyme. To clarify the structural basis for tight-binding inhibition, the crystal structure of the enzyme complexed with carpropamid was analyzed using diffraction data collected at 100 K. The structural model was refined to a crystallographic R-factor of 0.180 against reflections up to a resolution of 2.1 A. Carpropamid was bound in a hydrophobic cavity of the enzyme. Three types of interactions appeared to contribute to the binding. (i) A hydrogen bond was formed between a chloride atom in the dichloromethylethylcyclopropane ring of carpropamid and Asn-131 of the enzyme. (ii) The (chlorophenyl)ethyl group of carpropamid built strong contacts with Val-75, and this group further formed a cluster of aromatic rings together with four aromatic residues in the enzyme (Tyr-50, Phe-53, Phe-158, and Phe-162). (iii) Two hydration water molecules bound to the carboxamide group of carpropamid, and they were further hydrogen-bonded to Tyr-30, Tyr-50, His-85, and His-110. As a result of interactions between carpropamid and the phenylalanine residues (Phe-158 and Phe-162) in the C-terminal region of the enzyme, the C-terminal region completely covered the inhibitor, ensuring its localization in the cavity.
About this Structure
2STD is a Single protein structure of sequence from Magnaporthe grisea with SO4 and CRP as ligands. Active as Scytalone dehydratase, with EC number 4.2.1.94 Full crystallographic information is available from OCA.
Reference
Cryogenic X-ray crystal structure analysis for the complex of scytalone dehydratase of a rice blast fungus and its tight-binding inhibitor, carpropamid: the structural basis of tight-binding inhibition., Nakasako M, Motoyama T, Kurahashi Y, Yamaguchi I, Biochemistry. 1998 Jul 14;37(28):9931-9. PMID:9665698
Page seeded by OCA on Thu Feb 21 18:49:31 2008
