Biological Assembly 1  

 3D View: Structure | Electron Density | Ligand Interaction

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Homo 2-mer - A2 

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

Macromolecule Content

• Total Structure Weight: 101.28 kDa 
• Atom Count: 7503 
• Residue Count: 903 
• Unique protein chains: 1

1PJQ

Structure and function of CysG, the multifunctional methyltransferase/dehydrogenase/ferrochelatase for siroheme synthesis

• DOI: 10.2210/pdb1PJQ/pdb

• Classification: TRANSFERASE/OXIDOREDUCTASE/LYASE
• Organism(s): Salmonella enterica subsp. enterica serovar Typhimurium
• Expression System: Salmonella enterica
• Mutation(s): Yes 


• Deposited: 2003-06-03 Released: 2003-12-02 
• Deposition Author(s): Stroupe, M.E., Leech, H.K., Daniels, D.S., Warren, M.J., Getzoff, E.D.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.21 Å
• R-Value Free: 0.273 
• R-Value Work: 0.235 
• R-Value Observed: 0.235 

Literature

CysG structure reveals tetrapyrrole-binding features and novel regulation of siroheme biosynthesis.

Stroupe, M.E., Leech, H.K., Daniels, D.S., Warren, M.J., Getzoff, E.D.

(2003) Nat Struct Biol 10: 1064-1073

• PubMed: 14595395 
• DOI: 10.1038/nsb1007
• Primary Citation of Related Structures:  
  1PJQ, 1PJT, 1PJS


• PubMed Abstract: 
  

Sulfur metabolism depends on the iron-containing porphinoid siroheme. In Salmonella enterica, the S-adenosyl-L-methionine (SAM)-dependent bismethyltransferase, dehydrogenase and ferrochelatase, CysG, synthesizes siroheme from uroporphyrinogen III (uro'gen III). The reactions mediated by CysG encompass two branchpoint intermediates in tetrapyrrole biosynthesis, diverting flux first from protoporphyrin IX biosynthesis and then from cobalamin (vitamin B(12)) biosynthesis. We determined the first structure of this multifunctional siroheme synthase by X-ray crystallography. CysG is a homodimeric gene fusion product containing two structurally independent modules: a bismethyltransferase and a dual-function dehydrogenase-chelatase. The methyltransferase active site is a deep groove with a hydrophobic patch surrounded by hydrogen bond donors. This asymmetric arrangement of amino acids may be important in directing substrate binding. Notably, our structure shows that CysG is a phosphoprotein. From mutational analysis of the post-translationally modified serine, we suggest a conserved role for phosphorylation in inhibiting dehydrogenase activity and modulating metabolic flux between siroheme and cobalamin pathways.

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Organizational Affiliation: 

Department of Molecular Biology and Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037, USA.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Siroheme synthase	A, B	457	Salmonella enterica subsp. enterica serovar Typhimurium	Mutation(s): 1  Gene Names: CYSG OR STM3477 EC: 2.1.1.107 (PDB Primary Data), 1 (PDB Primary Data), 4.99.1 (PDB Primary Data), 1.3.1.76 (UniProt), 4.99.1.4 (UniProt)
Find proteins for P25924 (Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720)) Explore P25924  Go to UniProtKB:  P25924

Small Molecules

Ligands 3 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
SAH	B	S-ADENOSYL-L-HOMOCYSTEINE C14 H20 N6 O5 S ZJUKTBDSGOFHSH-WFMPWKQPSA-N
PGE	A	TRIETHYLENE GLYCOL C6 H14 O4 ZIBGPFATKBEMQZ-UHFFFAOYSA-N
ACT	A, B	ACETATE ION C2 H3 O2 QTBSBXVTEAMEQO-UHFFFAOYSA-M

Modified Residues  1 Unique
ID	Chains	Type	Formula	2D Diagram	Parent
SEP	A,B	L-PEPTIDE LINKING	C3 H8 N O6 P		SER

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.21 Å
• R-Value Free: 0.273 
• R-Value Work: 0.235 
• R-Value Observed: 0.235 
• Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 60.734	α = 90
b = 121.493	β = 90
c = 130.79	γ = 90

Software Package:

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

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2003-06-03 
• Released Date: 2003-12-02 
Deposition Author(s): Stroupe, M.E., Leech, H.K., Daniels, D.S., Warren, M.J., Getzoff, E.D.

Revision History 

• Version 1.0: 2003-12-02
  Type: Initial release
  
• Version 1.1: 2008-04-29
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance
• Version 1.3: 2014-11-12
  Changes: Structure summary