Annotation

Description

Quinolinate phosphoribosyltransferase (QAPRTase, EC 2.4.2.19) catalyzes the formation of nicotinate mononucleotide, carbon dioxide, and pyrophosphate from 5-phosphoribosyl 1-pyrophosphate (PRPP) and quinolinic acid (QA, pyridine 2,3-dicarboxylic acid). The 2.0 A resolution crystal structure of apo-QAPRTase is a two-domain enzyme, which forms a dimer with the buried surface area of 4970 A2 in the crystal. In each chain, smaller bridging alpha/beta N-terminal domain and bigger TIM-barrel C-terminal domain are interconnected by a ~50 A long alpha helix. The C-terminal half of this helix represents the first helix in the TIM-barrel structure. The N-terminal domain resembles the Rossmann fold and covers the active site of the TIM-barrel part of the V. cholerae apo-QAPRTase.  

Functional assignment

Transferase 

Structure information

Unit cell parameters

Space Group

P 21 21 21  

Unit Cell

a=59.20Å, b=79.55Å, c=117.91Å
α=90.00, β=90.00, γ=90.00 

Solvent content

38.27  

Matthews coefficient

1.99  

Refinement

Data for the highest resolution shell is in parentheses.

Resolution range

29.60-2.00Å (2.05-2.00Å)  

R_all(%)

17.6 

R_work(%)

17.3 (16.6) 

R_free(%)

22.2 (21.8) 

Num. observed reflections

38067 (2691) 

Num. R_free reflections

1903 (154) 

Completeness(%)

99.7 (98.5) 

Model parameters

Num Atoms

4736  

Num Waters

414  

Num Hetatoms

422  

Model mean isotropic B factor

26.540Ų  

RMSD bond length

0.013Å  

RMSD bond angle

1.609°  

Filename uploaded

3PAJ.pdb (uploaded on Sep 28, 2011 11:17 AM)  

Inserted

Oct 29, 2010