Biological Assembly 1  

Global Symmetry: Cyclic - C3  (3D View)
Global Stoichiometry: Homo 3-mer - A3 

Biological assembly 1 generated by PQS (software)

Macromolecule Content

• Total Structure Weight: 22.39 kDa 
• Atom Count: 1,593 
• Modelled Residue Count: 156 
• Deposited Residue Count: 156 
• Unique protein chains: 1

 2UUI

Crystal structure of Human Leukotriene C4 Synthase

• PDB DOI: 10.2210/pdb2UUI/pdb

• Classification: LYASE
• Organism(s): Homo sapiens
• Expression System: Komagataella pastoris
• Mutation(s): No 
• Membrane Protein: Yes  PDBTMMemProtMDmpstruc


• Deposited: 2007-03-02 Released: 2007-07-17 
• Deposition Author(s): Martinez Molina, D., Wetterholm, A., Kohl, A., McCarthy, A.A., Niegowski, D., Ohlson, E., Hammarberg, T., Eshaghi, S., Haeggstrom, J.Z., Nordlund, P.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.00 Å
• R-Value Free: 0.237 
• R-Value Work: 0.196 
• R-Value Observed: 0.198 

Literature

Structural Basis for Synthesis of Inflammatory Mediators by Human Leukotriene C4 Synthase.

Martinez Molina, D., Wetterholm, A., Kohl, A., Mccarthy, A.A., Niegowski, D., Ohlson, E., Hammarberg, T., Eshaghi, S., Haeggstrom, J.Z., Nordlund, P.

(2007) Nature 448: 613

• PubMed: 17632546 
• DOI: 10.1038/nature06009
• Primary Citation of Related Structures:  
  2UUH, 2UUI


• PubMed Abstract: 
  

Cysteinyl leukotrienes are key mediators in inflammation and have an important role in acute and chronic inflammatory diseases of the cardiovascular and respiratory systems, in particular bronchial asthma. In the biosynthesis of cysteinyl leukotrienes, conversion of arachidonic acid forms the unstable epoxide leukotriene A4 (LTA4). This intermediate is conjugated with glutathione (GSH) to produce leukotriene C4 (LTC4) in a reaction catalysed by LTC4 synthase: this reaction is the key step in cysteinyl leukotriene formation. Here we present the crystal structure of the human LTC4 synthase in its apo and GSH-complexed forms to 2.00 and 2.15 A resolution, respectively. The structure reveals a homotrimer, where each monomer is composed of four transmembrane segments. The structure of the enzyme in complex with substrate reveals that the active site enforces a horseshoe-shaped conformation on GSH, and effectively positions the thiol group for activation by a nearby arginine at the membrane-enzyme interface. In addition, the structure provides a model for how the omega-end of the lipophilic co-substrate is pinned at one end of a hydrophobic cleft, providing a molecular 'ruler' to align the reactive epoxide at the thiol of glutathione. This provides new structural insights into the mechanism of LTC4 formation, and also suggests that the observed binding and activation of GSH might be common for a family of homologous proteins important for inflammatory and detoxification responses.

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Organizational Affiliation: 

Division of Biophysics, Karolinska Institutet, 17177 Stockholm, Sweden.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
LEUKOTRIENE C4 SYNTHASE	A	156	Homo sapiens	Mutation(s): 0  Gene Names: LTC4S EC: 4.4.1.20 (PDB Primary Data), 2.5.1 (UniProt) Membrane Entity: Yes
UniProt & NIH Common Fund Data Resources
Find proteins for Q16873 (Homo sapiens) Explore Q16873  Go to UniProtKB:  Q16873
PHAROS:  Q16873

Small Molecules

Ligands 4 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
LMT	E [auth A], F [auth A]	DODECYL-BETA-D-MALTOSIDE C24 H46 O11 NLEBIOOXCVAHBD-QKMCSOCLSA-N
PLM	G [auth A], H [auth A], I [auth A], J [auth A], K [auth A], L [auth A], M [auth A], N [auth A], Q [auth A], R [auth A], S [auth A], T [auth A], U [auth A], V [auth A]	PALMITIC ACID C16 H32 O2 IPCSVZSSVZVIGE-UHFFFAOYSA-N
SO4	O [auth A], P [auth A]	SULFATE ION O4 S QAOWNCQODCNURD-UHFFFAOYSA-L
NI	B [auth A], C [auth A], D [auth A]	NICKEL (II) ION Ni VEQPNABPJHWNSG-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.00 Å
• R-Value Free: 0.237 
• R-Value Work: 0.196 
• R-Value Observed: 0.198 
• Space Group: F 2 3

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 169.67	α = 90
b = 169.67	β = 90
c = 169.67	γ = 90

Software Package:

Software Name	Purpose
REFMAC	refinement

Structure Validation

Entry History 

Deposition Data

• Released Date: 2007-07-17 
Deposition Author(s): Martinez Molina, D., Wetterholm, A., Kohl, A., McCarthy, A.A., Niegowski, D., Ohlson, E., Hammarberg, T., Eshaghi, S., Haeggstrom, J.Z., Nordlund, P.

Revision History  

• Version 1.0: 2007-07-17
  Type: Initial release
  
• Version 1.1: 2011-05-08
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance