Crystal Structure of (+)-δ-Cadinene Synthase from Gossypium arboreum and Evolutionary Divergence of Metal Binding Motifs for Catalysis
| Autor: | David W. Christianson, Luigi Di Costanzo, Rudolf Konrad Allemann, Amang Li, Heather A. Gennadios, David James Miller, Veronica Gonzalez, Fanglei Yu |
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| Přispěvatelé: | Gennadios, H. A., Gonzalez, V., DI COSTANZO, Luigi, Li, A., Yu, F., Miller, D. J., Allemann, R. K., Christianson, D. W. |
| Rok vydání: | 2009 |
| Předmět: |
Models
Molecular Protein Conformation Stereochemistry Tree cotton Isomerase Crystallography X-Ray Biochemistry Article Evolution Molecular Inhibitory Concentration 50 Protein structure Farnesyl diphosphate synthase Polyisoprenyl Phosphates Catalytic Domain Magnesium Enzyme Inhibitors Binding site Isomerases Alanine Gossypium Binding Sites biology ATP synthase Chemistry Hydrogen Bonding Lyase biology.organism_classification Recombinant Proteins Kinetics Amino Acid Substitution Barium Metals Biocatalysis biology.protein |
| Zdroj: | Biochemistry. 48:6175-6183 |
| ISSN: | 1520-4995 0006-2960 |
| DOI: | 10.1021/bi900483b |
| Popis: | (+)-Delta-cadinene synthase (DCS) from Gossypium arboreum (tree cotton) is a sesquiterpene cyclase that catalyzes the cyclization of farnesyl diphosphate in the first committed step of the biosynthesis of gossypol, a phytoalexin that defends the plant from bacterial and fungal pathogens. Here, we report the X-ray crystal structure of unliganded DCS at 2.4 A resolution and the structure of its complex with three putative Mg(2+) ions and the substrate analogue inhibitor 2-fluorofarnesyl diphosphate (2F-FPP) at 2.75 A resolution. These structures illuminate unusual features that accommodate the trinuclear metal cluster required for substrate binding and catalysis. Like other terpenoid cyclases, DCS contains a characteristic aspartate-rich D(307)DTYD(311) motif on helix D that interacts with Mg(2+)(A) and Mg(2+)(C). However, DCS appears to be unique among terpenoid cyclases in that it does not contain the "NSE/DTE" motif on helix H that specifically chelates Mg(2+)(B), which is usually found as the signature sequence (N,D)D(L,I,V)X(S,T)XXXE (boldface indicates Mg(2+)(B) ligands). Instead, DCS contains a second aspartate-rich motif, D(451)DVAE(455), that interacts with Mg(2+)(B). In this regard, DCS is more similar to the isoprenoid chain elongation enzyme farnesyl diphosphate synthase, which also contains two aspartate-rich motifs, rather than the greater family of terpenoid cyclases. Nevertheless, the structure of the DCS-2F-FPP complex shows that the structure of the trinuclear magnesium cluster is generally similar to that of other terpenoid cyclases despite the alternative Mg(2+)(B) binding motif. Analyses of DCS mutants with alanine substitutions in the D(307)DTYD(311) and D(451)DVAE(455) segments reveal the contributions of these segments to catalysis. |
| Databáze: | OpenAIRE |
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