4AOO: B. Subtilis Dutpase Yncf In Complex With Du Ppi And Mg In H32

Homotrimeric dUTPases contain three active sites, each formed by five conserved sequence motifs originating from all three subunits. The essential fifth motif lies in a flexible C-terminal arm which becomes ordered during catalysis and is disordered in most crystal structures. Previously, it has been shown that the two Bacillus subtilis dUTPases, YncF and YosS, differ from their orthologues in the position in the sequence of the essential Phe-lid residue, which stacks against the uracil base, and in the conformation of the general base aspartate, which points away from the active site. Here, three structures of the complex of YncF with dU-PPi-Mg(2+) and the structure of YosS complexed with dUMP are reported. dU-PPi-Mg(2+) triggers the ordering of both the C-terminal arm and a loop (residues 18-26) which is uniquely disordered in the Bacillus dUTPases. The dUMP complex suggests two stages in substrate release. Limited proteolysis experiments allowed those complexes in which C-terminal cleavage is hindered and those in which it can be assumed to be ordered to be identified. The results lead to the suggestion that dUpNHpp is not a perfect substrate mimic, at least for the B. subtilis enzymes, and provide new insights into the mechanism of these two dUTPases in comparison to their orthologues. The enzyme mechanism is reviewed using the present and previous crystal structures as snapshots along the reaction coordinate.
PDB ID: 4AOODownload
MMDB ID: 109137
PDB Deposition Date: 2012/3/29
Updated in MMDB: 2013/08
Experimental Method:
x-ray diffraction
Resolution: 2.3  Å
Source Organism:
Similar Structures:
Biological Unit for 4AOO: trimeric; determined by software (PISA)
Molecular Components in 4AOO
Label Count Molecule
Proteins (3 molecules)
Probable Deoxyuridine 5'-triphosphate Nucleotidohydrolase Yncf(Gene symbol: yncF)
Molecule annotation
Chemicals (10 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB