Biological Assembly 1  

 3D View: Structure | 1D-3D View | Electron Density | Validation Report | Ligand Interaction

Global Symmetry: Cyclic - C2  (3D View)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 34.81 kDa 
• Atom Count: 2601 
• Modelled Residue Count: 314 
• Deposited Residue Count: 326 
• Unique protein chains: 2

1Y7L

O-Acetylserine Sulfhydrylase Complex

• PDB DOI: 10.2210/pdb1Y7L/pdb

• Classification: TRANSFERASE
• Organism(s): Haemophilus influenzae
• Expression System: Escherichia coli BL21(DE3)
• Mutation(s): Yes 


• Deposited: 2004-12-09 Released: 2005-04-26 
• Deposition Author(s): Huang, B., Vetting, M.W., Roderick, S.L.

---

Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.55 Å
• R-Value Free: 0.207 
• R-Value Work: 0.197 
• R-Value Observed: 0.197 

Literature

The active site of O-acetylserine sulfhydrylase is the anchor point for bienzyme complex formation with serine acetyltransferase.

Huang, B., Vetting, M.W., Roderick, S.L.

(2005) J Bacteriol 187: 3201-3205

• PubMed: 15838047 
• DOI: 10.1128/JB.187.9.3201-3205.2005
• Primary Citation of Related Structures:  
  1Y7L


• PubMed Abstract: 
  

The biosynthesis of cysteine in bacteria and plants is carried out by a two-step pathway, catalyzed by serine acetyltransferase (SAT) and O-acetylserine sulfhydrylase (OASS; O-acetylserine [thiol] lyase). The aerobic form of OASS forms a tight bienzyme complex with SAT in vivo, termed cysteine synthase. We have determined the crystal structure of OASS in complex with a C-terminal peptide of SAT required for bienzyme complex formation. The binding site of the peptide is at the active site of OASS, and its C-terminal carboxyl group occupies the same anion binding pocket as the alpha-carboxylate of the O-acetylserine substrate of OASS. These results explain the partial inhibition of OASS by SAT on complex formation as well as the competitive dissociation of the complex by O-acetylserine.

---

Organizational Affiliation: 

Department of Biochemistry, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY 10461, USA.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
O-acetylserine sulfhydrylase	A	316	Haemophilus influenzae	Mutation(s): 1  Gene Names: cysK EC: 2.5.1.47
UniProt
Find proteins for P45040 (Haemophilus influenzae (strain ATCC 51907 / DSM 11121 / KW20 / Rd)) Explore P45040  Go to UniProtKB:  P45040

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details	Image
decamer fragment of Serine acetyltransferase	B [auth P]	10	N/A	Mutation(s): 0
UniProt
Find proteins for P43886 (Haemophilus influenzae (strain ATCC 51907 / DSM 11121 / KW20 / Rd)) Explore P43886  Go to UniProtKB:  P43886

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
SO4	C [auth A]	SULFATE ION O4 S QAOWNCQODCNURD-UHFFFAOYSA-L

Modified Residues  1 Unique
ID	Chains	Type	Formula	2D Diagram	Parent
LLP	A	L-PEPTIDE LINKING	C14 H22 N3 O7 P		LYS

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.55 Å
• R-Value Free: 0.207 
• R-Value Work: 0.197 
• R-Value Observed: 0.197 
• Space Group: I 4₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 112.569	α = 90
b = 112.569	β = 90
c = 45.799	γ = 90

Software Package:

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

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2004-12-09 
• Released Date: 2005-04-26 
Deposition Author(s): Huang, B., Vetting, M.W., Roderick, S.L.

Revision History  

• Version 1.0: 2005-04-26
  Type: Initial release
  
• Version 1.1: 2008-04-30
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance