3BNX: Crystal structure of Aristolochene synthase complexed with farnesyl diphosphate

The universal sesquiterpene precursor, farnesyl diphosphate (FPP), is cyclized in an Mg(2+)-dependent reaction catalyzed by the tetrameric aristolochene synthase from Aspergillus terreus to form the bicyclic hydrocarbon aristolochene and a pyrophosphate anion (PP(i)) coproduct. The 2.1-A resolution crystal structure determined from crystals soaked with FPP reveals the binding of intact FPP to monomers A-C, and the binding of PP(i) and Mg(2+)(B) to monomer D. The 1.89-A resolution structure of the complex with 2-fluorofarnesyl diphosphate (2F-FPP) reveals 2F-FPP binding to all subunits of the tetramer, with Mg(2+)(B)accompanying the binding of this analogue only in monomer D. All monomers adopt open activesite conformations in these complexes, but slight structural changes in monomers C and D of each complex reflect the very initial stages of a conformational transition to the closed state. Finally, the 2.4-A resolution structure of the complex with 12,13-difluorofarnesyl diphosphate (DF-FPP) reveals the binding of intact DF-FPP to monomers A-C in the open conformation and the binding of PP(i), Mg(2+)(B), and Mg(2+)(C) to monomer D in a predominantly closed conformation. Taken together, these structures provide 12 independent "snapshots" of substrate or product complexes that suggest a possible sequence for metal ion binding and conformational changes required for catalysis.
PDB ID: 3BNXDownload
MMDB ID: 63286
PDB Deposition Date: 2007/12/14
Updated in MMDB: 2017/12
Experimental Method:
x-ray diffraction
Resolution: 2.1  Å
Source Organism:
Similar Structures:
Biological Unit for 3BNX: tetrameric; determined by author
Molecular Components in 3BNX
Label Count Molecule
Proteins (4 molecules)
Aristolochene Synthase
Molecule annotation
Chemicals (11 molecules)
* Click molecule labels to explore molecular sequence information.

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