3LLK | pdb_00003llk

Sulfhydryl Oxidase Fragment of Human QSOX1

• PDB DOI: https://doi.org/10.2210/pdb3LLK/pdb

• Classification: OXIDOREDUCTASE
• Organism(s): Homo sapiens
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2010-01-29 Released: 2010-03-31 
• Deposition Author(s): Alon, A., Fass, D.

---

Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.00 Å
• R-Value Free: 
  0.272 (Depositor), 0.273 (DCC) 
• R-Value Work: 
  0.237 (Depositor), 0.240 (DCC) 

Starting Model: experimental

Literature

QSOX contains a pseudo-dimer of functional and degenerate sulfhydryl oxidase domains.

Alon, A., Heckler, E.J., Thorpe, C., Fass, D.

(2010) FEBS Lett 584: 1521-1525

• PubMed: 20211621 
• DOI: https://doi.org/10.1016/j.febslet.2010.03.001
• Primary Citation Related Structures: 
  3LLI, 3LLK


• PubMed Abstract: 
  

  Quiescin sulfhydryl oxidase (QSOX) catalyzes formation of disulfide bonds between cysteine residues in substrate proteins. Human QSOX1 is a multi-domain, monomeric enzyme containing a module related to the single-domain sulfhydryl oxidases of the Erv family. A partial QSOX1 crystal structure reveals a single-chain pseudo-dimer mimicking the quaternary structure of Erv enzymes. However, one pseudo-dimer "subunit" has lost its cofactor and catalytic activity. In QSOX evolution, a further concatenation to a member of the protein disulfide isomerase family resulted in an enzyme capable of both disulfide formation and efficient transfer to substrate proteins.

---

Organizational Affiliation: 
• Department of Structural Biology, Weizmann Institute of Science, Rehovot, Israel.

Biological Assembly 1  

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

Biological assembly 1 assigned by authors and generated by PISA (software)

Biological Assembly 2  

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

Biological assembly 2 assigned by authors and generated by PISA (software)

Biological Assembly 3  

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

Biological assembly 3 assigned by authors and generated by PISA (software)

Macromolecule Content 

• Total Structure Weight: 91.92 kDa 
• Atom Count: 6,469 
• Modeled Residue Count: 725 
• Deposited Residue Count: 783 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Sulfhydryl oxidase 1	A, B, C	261	Homo sapiens	Mutation(s): 0  Gene Names: QSCN6, QSOX1, UNQ2520/PRO6013 EC: 1.8.3.2
UniProt & NIH Common Fund Data Resources
Find proteins for O00391 (Homo sapiens) Explore O00391  Go to UniProtKB:  O00391
PHAROS:  O00391 GTEx:  ENSG00000116260

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
FAD	D [auth A], F [auth B], G [auth C]	FLAVIN-ADENINE DINUCLEOTIDE C27 H33 N9 O15 P2 VWWQXMAJTJZDQX-UYBVJOGSSA-N
FLC	E [auth A]	CITRATE ANION C6 H5 O7 KRKNYBCHXYNGOX-UHFFFAOYSA-K

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.00 Å
• R-Value Free:  0.272 (Depositor), 0.273 (DCC) 
• R-Value Work:  0.237 (Depositor), 0.240 (DCC) 

Space Group: C 2 2 2

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 83.481	α = 90
b = 161.573	β = 90
c = 121.94	γ = 90

Software Package:

Software Name	Purpose
PHASER	phasing
CNS	refinement
DENZO	data reduction
SCALEPACK	data scaling

Structure Validation

Entry History 

Deposition Data

• Released Date: 2010-03-31 
Deposition Author(s): Alon, A., Fass, D.

Revision History  

• Version 1.0: 2010-03-31
  Type: Initial release
  
• Version 1.1: 2011-07-13
  Changes: Version format compliance
• Version 1.2: 2023-09-06
  Changes: Data collection, Database references, Derived calculations, Refinement description
• Version 1.3: 2024-11-06
  Changes: Structure summary