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Structure of IDP90587

2.00 Angstrom resolution crystal structure of a catalytic subunit of an aspartate carbamoyltransferase (pyrB) from Yersinia pestis CO92

CSGID target
IDP90587  
PDB Id
3LXM (NCBI MMDB)  
Authors
Halavaty, A.S. Minasov, G. Dubrovska, I. Winsor, J. Shuvalova, L. Peterson, S. Anderson, W.F. Center for Structural Genomics of Infectious Diseases (CSGID)  
Responsible person
Andrei Halavaty  
Responsible lab
Northwestern University  
Deposition Date
2010-02-25  
Release Date
2010-03-16  

Annotation

Description
The enzyme aspartate carbamoyltransferase (ATCase) catalyzes the first step in the pyrimidine biosynthetic pathway. Crystal structure of a catalytic (C) subunit of the Yersinia pestis CO92 ATCase was solved by molecular replacement using the structure of the unregulated, N-phosphonacetyl-L-aspartate (PALA)-bound C subunit of ATCase from Escherichia coli (PDB ID 1EKX) as a model. Both proteins share 84 % sequence identity, are trimeric in the crystal and have 1.6 Å root-mean-square deviation (rmsd) of the C-alpha atoms. The structural discrepancy between two proteins is due to the greater overall flexibility and disorder in loops containing active-site residues of the ligand-free Y. pestis C trimer. In contrast, the E.coli PALA-free C trimer (PDB ID 3CSU) has 0.5 Å rmsd of the C-alpha atoms with its Y. pestis homolog. This indicates that binding of a substrate (substrate analog) alters structural perturbations. In order to understand the regulation mechanism of the Y. pestis ATCase, conformational states that account for allosteric structural changes in catalytic activity should be defined.  
Functional assignment
Transferase  

Ligands

Ligand code Name Ligand type

Structure information

Unit cell parameters

Space Group
P 21 21 21  
Unit Cell

a=67.62Å, b=120.41Å, c=126.70Å
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
30.00-2.00Å (2.05-2.00Å)  
Rall(%)
18.1  
Rwork(%)
17.9 (23.7)  
Rfree(%)
21.7 (29.1)  
Num. observed reflections
70860 (5080)  
Num. Rfree reflections
3543 (240)  
Completeness(%)
99.7 (98.1)  

Model parameters

Num Atoms
7196  
Num Waters
448  
Num Hetatoms
-6721  
Model mean isotropic B factor
45.810Å2  
RMSD bond length
0.015Å  
RMSD bond angle
1.674°  
Filename uploaded
idp90587a-deposit.pdb (uploaded on 2010-02-25 15:13:45-05)