5EAS

5-EPI-ARISTOLOCHENE SYNTHASE FROM NICOTIANA TABACUM

• PDB DOI: https://doi.org/10.2210/pdb5EAS/pdb

• Classification: ISOPRENOID SYNTHASE
• Organism(s): Nicotiana tabacum
• Expression System: Escherichia coli BL21(DE3)
• Mutation(s): No 


• Deposited: 1997-06-19 Released: 1997-10-15 
• Deposition Author(s): Starks, C.M., Back, K., Chappell, J., Noel, J.P.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.25 Å
• R-Value Free: 0.200 
• R-Value Work: 0.240 
• R-Value Observed: 0.240 

Literature

Structural basis for cyclic terpene biosynthesis by tobacco 5-epi-aristolochene synthase.

Starks, C.M., Back, K., Chappell, J., Noel, J.P.

(1997) Science 277: 1815-1820

• PubMed: 9295271 
• DOI: https://doi.org/10.1126/science.277.5333.1815
• Primary Citation of Related Structures:  
  5EAS, 5EAT, 5EAU


• PubMed Abstract: 
  

  Terpene cyclases catalyze the synthesis of cyclic terpenes with 10-, 15-, and 20-carbon acyclic isoprenoid diphosphates as substrates. Plants have been a source of these natural products by providing a homologous set of terpene synthases. The crystal structures of 5-epi-aristolochene synthase, a sesquiterpene cyclase from tobacco, alone and complexed separately with two farnesyl diphosphate analogs were analyzed. These structures reveal an unexpected enzymatic mechanism for the synthesis of the bicyclic product, 5-epi-aristolochene, and provide a basis for understanding the stereochemical selectivity displayed by other cyclases in the biosynthesis of pharmacologically important cyclic terpenes. As such, these structures provide templates for the engineering of novel terpene cyclases.

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Organizational Affiliation: 

Structural Biology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 63.12 kDa 
• Atom Count: 4,453 
• Modelled Residue Count: 514 
• Deposited Residue Count: 548 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
5-EPI-ARISTOLOCHENE SYNTHASE	A	548	Nicotiana tabacum	Mutation(s): 0  EC: 4.2.3.61 (UniProt), 4.2.3.226 (UniProt), 4.2.3.227 (UniProt)
UniProt
Find proteins for Q40577 (Nicotiana tabacum) Explore Q40577  Go to UniProtKB:  Q40577

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
MG	B [auth A], C [auth A]	MAGNESIUM ION Mg JLVVSXFLKOJNIY-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.25 Å
• R-Value Free: 0.200 
• R-Value Work: 0.240 
• R-Value Observed: 0.240 
• Space Group: P 4₁ 2₁ 2

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 124.73	α = 90
b = 124.73	β = 90
c = 118.94	γ = 90

Software Package:

Software Name	Purpose
VECSUM	model building
X-PLOR	model building
X-PLOR	refinement
DENZO	data reduction
SCALEPACK	data scaling
VECSUM	phasing
X-PLOR	phasing

Structure Validation

Entry History 

Deposition Data

• Released Date: 1997-10-15 
Deposition Author(s): Starks, C.M., Back, K., Chappell, J., Noel, J.P.

Revision History  

• Version 1.0: 1997-10-15
  Type: Initial release
  
• Version 1.1: 2008-03-25
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance
• Version 1.3: 2011-11-16
  Changes: Atomic model
• Version 1.4: 2024-03-13
  Changes: Data collection, Database references, Derived calculations, Other