Annotation

Description

The shikimate pathway links metabolism of carbohydrates to biosynthesis of aromatic compounds. In a sequence of seven steps, phosphoenolpyruvate and erythrose 4-phosphate are converted to chorismate, a precursor of the aromatic amino acids and many secondary aromatic metabolites. The shikimate pathway is essential for most bacteria and plants but absent in humans, making it an attractive target for the development of novel antibiotics. The third step in the pathway consists of the dehydration of dehydroquinate to dehydroshikimate. This reaction can be catalyzed by two enzyme families which utilize distinct mechanisms. While this protein is annotated as a type II dehydroquinate dehydratase and indeed has high sequence homology to active dehydratases, the structure reveals notable differences relative to all other characterized enzymes. Whereas other type II dehydratases assemble as dodecamers, comprised of a tetramer of trimers, this protein is assembles as a dimer, preserving the trimer-trimer interactions of the dodecamer. In other dehydratases a neighboring molecule in the dodecamer extends into the active site, making substantial contacts with the substrate and other active site residues. With the affected oligomeric assembly observed in this structure, comparable protein-protein interactions are noticeably lacking and much of the active site is disordered. At present, the source and functional implication of the unique these unique structural features await characterization.  

Functional assignment

Unknown 

Structure information

Unit cell parameters

Space Group

P 21 21 21  

Unit Cell

a=44.00Å, b=72.68Å, c=81.71Å
α=90.00, β=90.00, γ=90.00 

Solvent content

 

Matthews coefficient

 

Refinement

Data for the highest resolution shell is in parentheses.

Resolution range

29.94-1.60Å (1.64-1.60Å)  

R_all(%)

17.8 

R_work(%)

17.6 (22.7) 

R_free(%)

20.3 (26.6) 

Num. observed reflections

35401 (2344) 

Num. R_free reflections

1770 (109) 

Completeness(%)

99.8 (98.2) 

Model parameters

Num Atoms

2068  

Num Waters

214  

Num Hetatoms

220  

Model mean isotropic B factor

22.280Ų  

RMSD bond length

0.010Å  

RMSD bond angle

1.329°  

Filename uploaded

rcsb068421.pdb (uploaded on Oct 18, 2011 12:17 PM)  

Inserted

Oct 18, 2011