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 and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 35.23 kDa 
• Atom Count: 2584 
• Modelled Residue Count: 310 
• Deposited Residue Count: 322 
• Unique protein chains: 1

4LMB

Crystal structure analysis of O-acetylserine sulfhydrylase CysK2 complexed with cystine from Microcystis aeruginosa 7806

• PDB DOI: 10.2210/pdb4LMB/pdb

• Classification: TRANSFERASE
• Organism(s): Microcystis aeruginosa PCC 7806
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2013-07-10 Released: 2014-06-04 
• Deposition Author(s): Lu, M.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.91 Å
• R-Value Free: 0.230 
• R-Value Work: 0.202 
• R-Value Observed: 0.203 

Literature

Structural and biochemical analyses of Microcystis aeruginosa O-acetylserine sulfhydrylases reveal a negative feedback regulation of cysteine biosynthesis.

Lu, M., Xu, B.Y., Zhou, K., Cheng, W., Jiang, Y.L., Chen, Y., Zhou, C.Z.

(2014) Biochim Biophys Acta 1844: 308-315

• PubMed: 24275508 
• DOI: 10.1016/j.bbapap.2013.11.008
• Primary Citation of Related Structures:  
  4LMA, 4LMB


• PubMed Abstract: 
  

O-acetylserine sulfhydrylase (OASS) catalyzes the final step of cysteine biosynthesis from O-acetylserine (OAS) and inorganic sulfide in plants and bacteria. Bioinformatics analyses combined with activity assays enabled us to annotate the two putative genes of Microcystis aeruginosa PCC 7806 to CysK1 and CysK2, which encode the two 75% sequence-identical OASS paralogs. Moreover, we solved the crystal structures of CysK1 at 2.30Ǻ and cystine-complexed CysK2 at 1.91Ǻ, revealing a quite similar overall structure that belongs to the family of fold-type II PLP-dependent enzymes. Structural comparison indicated a significant induced fit upon binding to the cystine, which occupies the binding site for the substrate OAS and blocks the product release tunnel. Subsequent enzymatic assays further confirmed that cystine is a competitive inhibitor of the substrate OAS. Moreover, multiple-sequence alignment revealed that the cystine-binding residues are highly conserved in all OASS proteins, suggesting that this auto-inhibition of cystine might be a universal mechanism of cysteine biosynthesis pathway.

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Organizational Affiliation: 

Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China. Electronic address: [e-mail].

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Cysteine synthase	A	322	Microcystis aeruginosa PCC 7806	Mutation(s): 0  Gene Names: cysK, IPF_2058, IPF_3084 EC: 2.5.1.47
UniProt
Find proteins for A8YBP8 (Microcystis aeruginosa PCC 7806) Explore A8YBP8  Go to UniProtKB:  A8YBP8

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
PLP	D [auth A]	PYRIDOXAL-5'-PHOSPHATE C8 H10 N O6 P NGVDGCNFYWLIFO-UHFFFAOYSA-N
CYS	B [auth A], C [auth A]	CYSTEINE C3 H7 N O2 S XUJNEKJLAYXESH-REOHCLBHSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.91 Å
• R-Value Free: 0.230 
• R-Value Work: 0.202 
• R-Value Observed: 0.203 
• Space Group: P 6₅ 2 2

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 99.846	α = 90
b = 99.846	β = 90
c = 164.141	γ = 120

Software Package:

Software Name	Purpose
ADSC	data collection
AMoRE	phasing
REFMAC	refinement
HKL-2000	data reduction
SCALA	data scaling

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2013-07-10 
• Released Date: 2014-06-04 
Deposition Author(s): Lu, M.

Revision History  

• Version 1.0: 2014-06-04
  Type: Initial release