2QX0: Crystal Structure Of Yersinia Pestis Hppk (Ternary Complex)

6-Hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) is a key enzyme in the folate-biosynthetic pathway and is essential for microorganisms but absent from mammals. HPPK catalyzes Mg(2+)-dependent pyrophosphoryl transfer from ATP to 6-hydroxymethyl-7,8-dihydropterin (HP). Previously, three-dimensional structures of Escherichia coli HPPK (EcHPPK) have been determined at almost every stage of its catalytic cycle and the reaction mechanism has been established. Here, the crystal structure of Yersinia pestis HPPK (YpHPPK) in complex with HP and an ATP analog is presented together with thermodynamic and kinetic characterizations. The two HPPK molecules differ significantly in a helix-loop area (alpha2-Lp3). YpHPPK has lower affinities than EcHPPK for both nucleotides and HP, but its rate constants for the mechanistic steps of both chemical transformation and product release are comparable with those of EcHPPK. Y. pestis, which causes plague, is a category A select agent according to the Centers for Disease Control and Prevention (CDC). Therefore, these structural and biochemical data are valuable for the design of novel medical countermeasures against plague.
PDB ID: 2QX0Download
MMDB ID: 60275
PDB Deposition Date: 2007/8/10
Updated in MMDB: 2007/11
Experimental Method:
x-ray diffraction
Resolution: 1.8  Å
Source Organism:
Similar Structures:
Biological Unit for 2QX0: dimeric; determined by author and by software (PISA)
Molecular Components in 2QX0
Label Count Molecule
Proteins (2 molecules)
7,8-dihydro-6-hydroxymethylpterin- Pyrophosphokinase
Molecule annotation
Chemicals (8 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB