Structure of fructose bisphosphate aldolase fromEncephalitozoon cuniculi

Abstract

PDB References: fructose bisphosphate aldolase, phosphate-bound, 3mbd; FBP-bound, 3mbf.Fructose bisphosphate aldolose (FBPA) enzymes have been found in a broad range of eukaryotic and prokaryotic organisms. FBPA catalyses the cleavage of fructose 1,6-bisphosphate into glyceraldehyde 3-phosphate and dihydroxyacetone phosphate. The SSGCID has reported several FBPA structures from pathogenic sources. Bioinformatic analysis of the genome of the eukaryotic microsporidian parasite Encephalitozoon cuniculi revealed an FBPA homolog. The structures of this enzyme in the presence of the native substrate FBP and also with the partial substrate analog phosphate are reported. The purified enzyme crystallized in 90 mM Bis-Tris propane pH 6.5, 18% PEG 3350, 18 mM NaKHPO 4 , 10 mM urea for the phosphate-bound form and 100 mM Bis-Tris propane pH 6.5, 20% PEG 3350, 20 mM fructose 1,6-bisphosphate for the FBPbound form. In both cases protein was present at 25 mg ml À1 and the sittingdrop vapour-diffusion method was used. For the FBP-bound form, a data set to 2.37 Å resolution was collected from a single crystal at 100 K. The crystal belonged to the orthorhombic space group C222 1 , with unit-cell parameters a = 121.46, b = 135.82, c = 61.54 Å . The structure was refined to a final free R factor of 20.8%. For the phosphate-bound form, a data set was collected to 2.00 Å resolution. The space group was also C222 1 and the unit-cell parameters were a = 121.96, b = 137.61, c = 62.23 Å . The structure shares the typical barrel tertiary structure reported for previous FBPA structures and exhibits the same Schiff base in the active site. The quaternary structure is dimeric. This work provides a direct experimental result for the substrate-binding conformation of the product state of E. cuniculi FBPA.

Structural and Functional Characterization of Methicillin-ResistantStaphylococcus aureus’sClass IIb Fructose 1,6-Bisphosphate Aldolase

“…Unlike the active site loop within class II FBAs, the β6α6 loop containing residues 177–191, and previously termed the Z-loop, is almost always well-defined structurally. ,,,,,,,,− This loop forms part of the substrate pocket as well as contains a histidine residue involved in coordination with the active site Zn­(II) ion . Between class IIb FBAs, such as HpFBA, whose structures have been reported, and SaFBA, HpFBA possess two additional residues within this region.…”

Structure of fructose bisphosphate aldolase fromBartonella henselaebound to fructose 1,6-bisphosphate

“…The structure obtained of the reactant Schiff-base state is similar to those of other aldolases in the reactant state [PDB entries 1zai (St-Jean et al, 2005), 3mbf (Gardberg et al, 2011) and2qdg (Lafrance-Vanasse &Sygusch, 2007)], especially rabbit muscle FBPA A (PDB entry 1zai). The similarity to the active site of mammalian FBPA A suggests that the design of a specific inhibitor for BhFBPA (that does not inhibit the human enzyme) would be exceptionally challenging and would have to rely on exploiting very minor differences in the chemical environment in and near the active site.…”

Crystal structure of chloroplast fructose-1,6-bisphosphate aldolase from the green algaChlamydomonas reinhardtii

“…This site is a strongly electropositive pocket, containing one or two sulfate ions captured in the crystallization solution and several water molecules (figure 3). Active site of class I aldolase have already been described structurally and chemically in various organisms (Dalby, Dauter et al 1999) (St-Jean, Lafrance-Vanasse et al 2005) (Lafrance-Vanasse and Sygusch 2007) (Gardberg, Abendroth et al 2011) (Gardberg, Sankaran et al 2011). Eleven catalytic residues described in these articles are present in Chlamydomonas reinhardtii FBA3 at the following positions: Asp52, Ser54, Thr57, Lys125, Lys164, Arg166, Glu204, Glu206, Lys246, Ser288, and Arg318.…”