5dz2

Geosmin synthase from Streptomyces coelicolor N-terminal domain complexed with three Mg2+ ions and alendronic acid

spinqualitylabelsall models 5dz2, resolution 2.11Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5dz2 is a 2 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: 212, MG Related: 5dw7 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum Function [CYC2_STRCO] Tow-domain protein where the N-terminal domain catalyzes the cyclization of farnesyl diphosphate (FPP) to a 85:15 mixture of the sesquiterpene alcohol germacradienol and the sesquiterpene hydrocarbon germacrene D. The C-terminal domain partially converts the germacradienol formed into geosmin, the characteristic odoriferous ('earthy aroma') constituent of Streptomyces species. Publication Abstract from PubMed Geosmin synthase from Streptomyces coelicolor (ScGS) catalyzes an unusual, metal-dependent terpenoid cyclization and fragmentation reaction sequence. Two distinct active sites are required for catalysis: the N-terminal domain catalyzes the ionization and cyclization of farnesyl diphosphate to form germacradienol and inorganic pyrophosphate (PPi), and the C-terminal domain catalyzes the protonation, cyclization, and fragmentation of germacradienol to form geosmin and acetone through a retro-Prins reaction. A unique alphaalpha domain architecture is predicted for ScGS based on amino acid sequence: each domain contains the metal-binding motifs typical of a class I terpenoid cyclase, and each domain requires Mg2+ for catalysis. Here, we report the X-ray crystal structure of the unliganded N-terminal domain of ScGS and the structure of its complex with three Mg2+ ions and alendronate. These structures highlight conformational changes required for active site closure and catalysis. Although neither full-length ScGS nor constructs of the C-terminal domain could be crystallized, homology models of the C-terminal domain were constructed on the basis of approximately 36% sequence identity with the N-terminal domain. Small-angle X-ray scattering experiments yield low-resolution molecular envelopes into which the N-terminal domain crystal structure and the C-terminal domain homology model were fit, suggesting possible alphaalpha domain architectures as frameworks for bifunctional catalysis. Structural Studies of Geosmin Synthase, a Bifunctional Sesquiterpene Synthase with alphaalpha Domain Architecture That Catalyzes a Unique Cyclization-Fragmentation Reaction Sequence.,Harris GG, Lombardi PM, Pemberton TA, Matsui T, Weiss TM, Cole KE, Koksal M, Murphy FV 4th, Vedula LS, Chou WK, Cane DE, Christianson DW Biochemistry. 2015 Dec 8;54(48):7142-7155. Epub 2015 Nov 24. PMID:26598179 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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