2xem

Induced-fit and allosteric effects upon polyene binding revealed by crystal structures of the Dynemicin thioesterase

spinqualitylabelsall models 2xem, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2xem is a 4 chain structure with sequence from Micromonospora chersina. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.1Å Ligands: SSV Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q84HI7_9ACTN Publication Abstract from PubMed Dynemicins are structurally related 10-membered enediyne natural products isolated from Micromonospora chernisa with potent antitumor and antibiotic activity. The early biosynthetic steps of the enediyne moiety of dynemicins are catalyzed by an iterative polyketide synthase (DynE8) and a thioesterase (DynE7). Recent studies indicate that the function of DynE7 is to off-load the linear biosynthetic intermediate assembled on DynE8. Here, we report crystal structures of DynE7 in its free form at 2.7 A resolution and of DynE7 in complex with the DynE8-produced all-trans pentadecen-2-one at 2.1 A resolution. These crystal structures reveal that upon ligand binding, significant conformational changes throughout the substrate-binding tunnel result in an expanded tunnel that traverses an entire monomer of the tetrameric DynE7 protein. The enlarged inner segment of the channel binds the carbonyl-conjugated polyene mainly through hydrophobic interactions, whereas the putative catalytic residues are located in the outer segment of the channel. The crystallographic information reinforces an unusual catalytic mechanism that involves a strictly conserved arginine residue for this subfamily of hot-dog fold thioesterases, distinct from the typical mechanism for hot-dog fold thioesterases that utilizes an acidic residue for catalysis. Induced-fit upon Ligand Binding Revealed by Crystal Structures of the Hot-dog Fold Thioesterase in Dynemicin Biosynthesis.,Liew CW, Sharff A, Kotaka M, Kong R, Sun H, Qureshi I, Bricogne G, Liang ZX, Lescar J J Mol Biol. 2010 Oct 1. PMID:20888341 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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