3OHI image
Deposition Date 2010-08-17
Release Date 2011-01-19
Last Version Date 2023-09-06
Entry Detail
PDB ID:
3OHI
Keywords:
Title:
Structure of Giardia fructose-1,6-biphosphate aldolase in complex with 3-hydroxy-2-pyridone
Biological Source:
Source Organism:
Host Organism:
Method Details:
Experimental Method:
Resolution:
2.30 Å
R-Value Free:
0.27
R-Value Work:
0.19
R-Value Observed:
0.20
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Putative fructose-1,6-bisphosphate aldolase
Chain IDs:A, B
Chain Length:323
Number of Molecules:2
Biological Source:Giardia intestinalis
Primary Citation
Rational design, synthesis and evaluation of first generation inhibitors of the Giardia lamblia fructose-1,6-biphosphate aldolase.
J.Inorg.Biochem. 105 509 517 (2010)
PMID: 21333622 DOI: 10.1016/j.jinorgbio.2010.12.012

Abstact

Inhibitors of the Giardia lamblia fructose 1,6-bisphosphate aldolase (GlFBPA), which transforms fructose 1,6-bisphosphate (FBP) to dihydroxyacetone phosphate and glyceraldehyde 3-phosphate, were designed based on 3-hydroxy-2-pyridone and 1,2-dihydroxypyridine scaffolds that position two negatively charged tetrahedral groups for interaction with substrate phosphate binding residues, a hydrogen bond donor to the catalytic Asp83, and a Zn(2+) binding group. The inhibition activities for the GlFBPA catalyzed reaction of FBP of the prepared alkyl phosphonate/phosphate substituted 3-hydroxy-2-pyridinones and a dihydroxypyridine were determined. The 3-hydroxy-2-pyridone inhibitor 8 was found to bind to GlFBPA with an affinity (K(i)=14μM) that is comparable to that of FBP (K(m)=2μM) or its inert analog TBP (K(i)=1μM). The X-ray structure of the GlFBPA-inhibitor 8 complex (2.3Å) shows that 8 binds to the active site in the manner predicted by in silico docking with the exception of coordination with Zn(2+). The observed distances and orientation of the pyridone ring O=C-C-OH relative to Zn(2+) are not consistent with a strong interaction. To determine if Zn(2+)coordination occurs in the GlFBPA-inhibitor 8 complex in solution, EXAFS spectra were measured. A four coordinate geometry comprised of the three enzyme histidine ligands and an oxygen atom from the pyridone ring O=C-C-OH was indicated. Analysis of the Zn(2+) coordination geometries in recently reported structures of class II FBPAs suggests that strong Zn(2+) coordination is reserved for the enediolate-like transition state, accounting for minimal contribution of Zn(2+) coordination to binding of 8 to GlFBPA.

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