Overexpression, physicochemical characterization, and modeling of a hyperthermophilic pyrococcus furiosus type 2 IPP isomerase.

In the first step of this study, type 2 isopentenyl diphosphate isomerase (IDI2) from Pyrococcus furiosus (pf-IDI2), a hyperthermophilic microorganism, was cloned and overexpressed in E. coli. After purification, hyperthermophilic behavior of this protein was approached by means of enzymatic assays and thermal denaturation studies.

Structural role for Tyr-104 in Escherichia coli isopentenyl-diphosphate isomerase: site-directed mutagenesis, enzymology, and protein crystallography.

Isopentenyl-diphosphate (IPP):dimethylallyl diphosphate isomerase is a key enzyme in the biosynthesis of isoprenoids. The mechanism of the isomerization reaction involves protonation of the unactivated carbon-carbon double bond in the substrate, but identity of the acidic moiety providing the proton is still not clear. Multiple sequence alignments and geometrical features observed in crystal structures of complexes with IPP isomerase suggest that Tyr-104 could play an important role during catalysis.

Evidence of an equilibrium between selenides and osmium(VIII) reagents and selenoxides and osmium(VI) reagents.

Driving the equilibrium between selenides and osmium(VIII) reagents with selenoxides and osmium(VI) by a subsequent reaction (rearrangement of allyl selenoxides to allyl alcohols or addition of osmium(VIII) species on C=C double bonds) to one side, allows the transformation of methyl geranyl selenides to linalool and of methyl citronellyl selenoxide to 6,7-dihydroxy citronellyl selenide.