Evidence of a Novel Mevalonate Pathway in Archaea

Vinokur, J.M.; Korman, Tyler P.; Cao, Zi-Jun; Bowie, James U.

doi:10.1021/bi500566q

Cited by 52 publications

(80 citation statements)

References 33 publications

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“…In the modified pathways, isopentenyl diphosphate is formed from isopentenyl phosphate, which is not an intermediate of the classical pathway. However, the biosynthetic routes to convert MVA into isopentenyl phosphate are different among archaeal lineages; for example, MVA 5-kinase and phosphomevalonate decarboxylase are used in a halophilic archaeon Haloferax volcanii (53), and MVA 3-kinase, MVA-3-phosphate 5-kinase, and probably MVA-3,5-bisphosphate decarboxylase are used in a thermophilic archaeon, Thermoplasma acidophilum (54,55). Among these recently discovered enzymes, phosphomevalonate decarboxylase and MVA 3-kinase are closely related to DMD.…”

Section: Discussionmentioning

confidence: 99%

In Vivo Formation of the Protein Disulfide Bond That Enhances the Thermostability of Diphosphomevalonate Decarboxylase, an Intracellular Enzyme from the Hyperthermophilic Archaeon Sulfolobus solfataricus

et al. 2015

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In the present study, the crystal structure of recombinant diphosphomevalonate decarboxylase from the hyperthermophilic archaeon Sulfolobus solfataricus was solved as the first example of an archaeal and thermophile-derived diphosphomevalonate decarboxylase. The enzyme forms a homodimer, as expected for most eukaryotic and bacterial orthologs. Interestingly, the subunits of the homodimer are connected via an intersubunit disulfide bond, which presumably formed during the purification process of the recombinant enzyme expressed in Escherichia coli. When mutagenesis replaced the disulfide-forming cysteine residue with serine, however, the thermostability of the enzyme was significantly lowered. In the presence of ␤-mercaptoethanol at a concentration where the disulfide bond was completely reduced, the wild-type enzyme was less stable to heat. Moreover, Western blot analysis combined with nonreducing SDS-PAGE of the whole cells of S. solfataricus proved that the disulfide bond was predominantly formed in the cells. These results suggest that the disulfide bond is required for the cytosolic enzyme to acquire further thermostability and to exert activity at the growth temperature of S. solfataricus. IMPORTANCEThis study is the first report to describe the crystal structures of archaeal diphosphomevalonate decarboxylase, an enzyme involved in the classical mevalonate pathway. A stability-conferring intersubunit disulfide bond is a remarkable feature that is not found in eukaryotic and bacterial orthologs. The evidence that the disulfide bond also is formed in S. solfataricus cells suggests its physiological importance.

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Section: Discussionmentioning

confidence: 99%

In Vivo Formation of the Protein Disulfide Bond That Enhances the Thermostability of Diphosphomevalonate Decarboxylase, an Intracellular Enzyme from the Hyperthermophilic Archaeon Sulfolobus solfataricus

et al. 2015

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“…Two proteins from the archeon Thermoplasma acidophilum , Ta1305 and Ta0893, were computationally annotated in the year 2000 as “mevalonate pyrophosphate decarboxylase”9. As reported recently, however, Ta1305 is actually mevalonate 3-kinase (EC 2.7.1.185)17. A structural homology model of Ta0893 made with PHYRE2 suggested significant similarity to mevalonate 5-pyrophosphate decarboxylase from yeast (PDB: 1FI4, confidence score of 100%) and contained the invariant Asp/Lys/Arg catalytic triad necessary for decarboxylation in the correct positions (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…While the classical archaeal pathway phosphorylates mevalonate at the 5-OH position to yield mevalonate 5-phosphate, and then uses MMD to produce IP in an ATP dependent reaction, the T. acidophilum pathway produces the same end product, but uses a different set of enzymes and metabolites17. The pathway in T. acidophilum phosphorylates mevalonate at the 3-OH position and the 5-OH position sequentially by two distinct enzymes to yield mevalonate 3,5-bisphosphate.…”

Section: Discussionmentioning

confidence: 99%

“…The mechanism was previously thought to occur via a single step in which the phosphorylation of the 3-OH position leads to an unstable and transient intermediate that rapidly decomposes into IPP, CO 2 and PO 4 2627. Our previous identification of mevalonate 3,5-bisphosphate as a stable metabolite suggested that decarboxylation is not spontaneous and must be carried out by enzyme catalysis1736. The identification of MBD provides further support for the two-step model since T. acidophilum carries out the reactions through two entirely separate enzymes.…”

Section: Discussionmentioning

confidence: 99%

“…1, red pathway)1718. However, the putative mevalonate 3,5-bisphosphate decarboxylase (MBD) remained unidentified to complete this alternative archaeal pathway.…”

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confidence: 99%

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An Adaptation To Life In Acid Through A Novel Mevalonate Pathway

Vinokur

Cummins

Korman

et al. 2016

Sci Rep

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Extreme acidophiles are capable of growth at pH values near zero. Sustaining life in acidic environments requires extensive adaptations of membranes, proton pumps, and DNA repair mechanisms. Here we describe an adaptation of a core biochemical pathway, the mevalonate pathway, in extreme acidophiles. Two previously known mevalonate pathways involve ATP dependent decarboxylation of either mevalonate 5-phosphate or mevalonate 5-pyrophosphate, in which a single enzyme carries out two essential steps: (1) phosphorylation of the mevalonate moiety at the 3-OH position and (2) subsequent decarboxylation. We now demonstrate that in extreme acidophiles, decarboxylation is carried out by two separate steps: previously identified enzymes generate mevalonate 3,5-bisphosphate and a new decarboxylase we describe here, mevalonate 3,5-bisphosphate decarboxylase, produces isopentenyl phosphate. Why use two enzymes in acidophiles when one enzyme provides both functionalities in all other organisms examined to date? We find that at low pH, the dual function enzyme, mevalonate 5-phosphate decarboxylase is unable to carry out the first phosphorylation step, yet retains its ability to perform decarboxylation. We therefore propose that extreme acidophiles had to replace the dual-purpose enzyme with two specialized enzymes to efficiently produce isoprenoids in extremely acidic environments.

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