3ohi
Structure of Giardia fructose-1,6-biphosphate aldolase in complex with 3-hydroxy-2-pyridone
Structural highlights
FunctionPublication Abstract from PubMedInhibitors 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)=14muM) that is comparable to that of FBP (K(m)=2muM) or its inert analog TBP (K(i)=1muM). The X-ray structure of the GlFBPA-inhibitor 8 complex (2.3A) 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. Rational design, synthesis and evaluation of first generation inhibitors of the Giardia lamblia fructose-1,6-biphosphate aldolase.,Li Z, Liu Z, Cho DW, Zou J, Gong M, Breece RM, Galkin A, Li L, Zhao H, Maestas GD, Tierney DL, Herzberg O, Dunaway-Mariano D, Mariano PS J Inorg Biochem. 2010 Dec 30;105(4):509-517. PMID:21333622[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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