Recombinant Saccharomyces cerevisiae Diphosphomevalonate decarboxylase (MVD1)
Description
Introduction to Recombinant Saccharomyces cerevisiae Diphosphomevalonate Decarboxylase (MVD1)
Recombinant Saccharomyces cerevisiae Diphosphomevalonate Decarboxylase (MVD1) is a genetically engineered enzyme critical for the mevalonate pathway, which produces isopentenyl diphosphate (IPP)—a universal precursor for sterols (e.g., ergosterol) and non-sterol isoprenoids . MVD1 catalyzes the ATP-dependent decarboxylation of (R)-5-diphosphomevalonate (MVAPP) to IPP, CO₂, ADP, and phosphate . This reaction represents the final step in the mevalonate pathway, making MVD1 indispensable for cellular processes such as membrane integrity, protein prenylation, and stress adaptation .
Enzyme Classification and Gene Information
Mechanism of Action
The reaction occurs in two stages:
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Phosphorylation: ATP transfers a phosphate to MVAPP’s C3 hydroxyl, forming 3-phospho-MVAPP .
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Decarboxylation: Concerted elimination of CO₂ and phosphate yields IPP .
This mechanism relies on a transient β-carboxy carbonium intermediate, stabilized by active-site residues .
Role in Metabolic Engineering
Recombinant S. cerevisiae strains expressing MVD1 are pivotal in biofuel production. For example:
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Xylose Fermentation: Strains like MA-R4 (industrial) show 1.5× higher growth rates than laboratory strains (MA-B4) when fermenting xylose, linked to upregulated MVD1 expression under stress .
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Ethanol Yield: Enhanced MVD1 activity correlates with improved ATP synthesis and ethanol tolerance .
Stress Adaptation and Ergosterol Biosynthesis
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Ethanol Stress: Overexpression of MVD1 in Aspergillus oryzae delays sporulation but increases vacuolar localization, suggesting ergosterol’s role in membrane stability .
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Thermosensitivity: A single Leu-to-Pro mutation in MVD1 disrupts dimerization, causing temperature-sensitive lethality in yeast .
Comparative Analysis of MVD1 Across Species
Table 1: Biochemical Properties of MVD1
| Property | Value |
|---|---|
| Reaction | MVAPP → IPP + CO₂ + ADP + phosphate |
| Cofactors | ATP, Mg²⁺ |
| KM for MVAPP (yeast) | 0.14 mM |
| Optimal pH | 6.5–7.5 |
Table 2: Genetic and Functional Insights
Future Directions
Research priorities include resolving substrate-bound crystal structures and engineering MVD1 variants for enhanced catalytic efficiency in industrial bioprocesses . Understanding its regulation under metabolic stress (e.g., ethanol inhibition) remains critical for optimizing biofuel yields .
