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PDBsum entry 3u55

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protein ligands links
Ligase PDB id
3u55
Jmol
Contents
Protein chain
227 a.a.
Ligands
SO4 ×2
ACT
Waters ×217
PDB id:
3u55
Name: Ligase
Title: Crystal structure (type-2) of saicar synthetase from pyrococ horikoshii ot3
Structure: Phosphoribosylaminoimidazole-succinocarboxamide s chain: a. Synonym: saicar synthetase. Engineered: yes
Source: Pyrococcus horikoshii. Organism_taxid: 70601. Strain: ot3. Gene: ph0239, purc. Expressed in: escherichia coli. Expression_system_taxid: 562.
Resolution:
1.90Å     R-factor:   0.186     R-free:   0.229
Authors: K.Manjunath,S.P.Kanaujia,S.Kanagaraj,J.Jeyakanthan,K.Sekar
Key ref: K.Manjunath et al. (2013). Structure of SAICAR synthetase from Pyrococcus horikoshii OT3: insights into thermal stability. Int J Biol Macromol, 53, 7. PubMed id: 23137517
Date:
11-Oct-11     Release date:   17-Oct-12    
PROCHECK
Go to PROCHECK summary
 Headers
 References

Protein chain
Pfam   ArchSchema ?
O57978  (PUR7_PYRHO) -  Phosphoribosylaminoimidazole-succinocarboxamide synthase
Seq:
Struc:
238 a.a.
227 a.a.
Key:    PfamA domain  Secondary structure  CATH domain

 Enzyme reactions 
   Enzyme class: E.C.6.3.2.6  - Phosphoribosylaminoimidazolesuccinocarboxamide synthase.
[IntEnz]   [ExPASy]   [KEGG]   [BRENDA]

      Pathway:
Purine Biosynthesis (late stages)
      Reaction: ATP + 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxylate + L-aspartate = ADP + phosphate + (S)-2-(5-amino-1-(5-phospho-D- ribosyl)imidazole-4-carboxamido)succinate
ATP
+ 5-amino-1-(5-phospho-D-ribosyl)imidazole-4-carboxylate
+
L-aspartate
Bound ligand (Het Group name = ACT)
matches with 44.44% similarity
= ADP
+ phosphate
+ (S)-2-(5-amino-1-(5-phospho-D- ribosyl)imidazole-4-carboxamido)succinate
Molecule diagrams generated from .mol files obtained from the KEGG ftp site
 Gene Ontology (GO) functional annotation 
  GO annot!
  Biological process     purine nucleotide biosynthetic process   2 terms 
  Biochemical function     nucleotide binding     4 terms  

 

 
    reference    
 
 
Int J Biol Macromol 53:7 (2013)
PubMed id: 23137517  
 
 
Structure of SAICAR synthetase from Pyrococcus horikoshii OT3: insights into thermal stability.
K.Manjunath, S.P.Kanaujia, S.Kanagaraj, J.Jeyakanthan, K.Sekar.
 
  ABSTRACT  
 
The first native crystal structure of Phosphoribosylaminoimidazole-succinocarboxamide synthetase (SAICAR synthetase) from a hyperthermophilic organism Pyrococcus horikoshii OT3 was determined in two space groups H3 (Type-1: Resolution 2.35Å) and in C222(1) (Type-2: Resolution 1.9Å). Both are dimeric but Type-1 structure exhibited hexameric arrangement due to the presence of cadmium ions. A comparison has been made on the sequence and structures of all SAICAR synthetases to better understand the differences between mesophilic, thermophilic and hyperthermophilic SAICAR synthetases. These SAICAR synthetases are reasonably similar in sequence and three-dimensional structure; however, differences were visible only in the subtler details of percentage composition of the sequences, salt bridge interactions and non-polar contact areas.