Annotation

Description

Also known as SAICAR synthetase, phosphoribosylaminoimidazole-succinocarboxamide synthase catalyzes the seventh step in the de novo purine biosynthetic pathway; the ATP-dependent conversion of 5'-phosphoribosyl-5-aminoimidazole-4-carboxylic acid and aspartic acid to SAICAR. Overall the 1.4 A structure is similar to other reported structures of an alpha-beta fold with two anti-parallel beta-sheets surrounded by seven alpha helices. The structure is a symmetric dimer formed by the interaction between the small alpha-helices and the edges of the beta-sheet in the middle domain. An ADP and an AMP molecules processed from ATP added during the crystallization were found in the groove formed between the two beta-sheets in each monomer. 

Functional assignment

 

Structure information

Unit cell parameters

Space Group

P 21 21 2  

Unit Cell

a=80.88Å, b=148.91Å, c=45.31Å
α=90.00, β=90.00, γ=90.00 

Solvent content

50.76  

Matthews coefficient

2.5  

Refinement

Data for the highest resolution shell is in parentheses.

Resolution range

38.21-1.40Å (1.45-1.40Å)  

R_all(%)

14.4 

R_work(%)

14.3 (19.8) 

R_free(%)

16.1 (21.8) 

Num. observed reflections

113879 (10703) 

Num. R_free reflections

5705 (522) 

Completeness(%)

99.9 (100.0) 

Model parameters

Num Atoms

4948  

Num Waters

711  

Num Hetatoms

82  

Model mean isotropic B factor

19.700Ų  

RMSD bond length

0.012Å  

RMSD bond angle

1.500°  

RMSD dihedral angle

18.288°

 

Filename uploaded

rcsb060288-rev.pdb (uploaded on Jul 14, 2010 8:01 AM)  

Inserted

Jul 06, 2010