Recombinant Zea mays 15-cis-zeta-carotene isomerase, chloroplastic
Description
Biochemical Characteristics
Recombinant Z-ISO is produced via heterologous expression in Escherichia coli ( ). Key features include:
The enzyme’s activity depends on a heme B cofactor, which undergoes redox-regulated conformational changes to facilitate substrate binding ( ). AlphaFold structural models predict a membrane-integrated topology with conserved substrate-binding pockets across plant and cyanobacterial homologs ( ).
Functional Role in Carotenoid Biosynthesis
Z-ISO catalyzes the cis-to-trans isomerization of the central 15–15′ double bond in ζ-carotene, enabling downstream desaturation and cyclization reactions ( ). Key findings:
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Light-Independent Activity: Essential in dark tissues (e.g., roots, etiolated leaves) where photoisomerization is absent ( ).
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Redox Sensitivity: Activity correlates with plastid redox state, linking carotenoid synthesis to cellular metabolic signals ( ).
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Epistatic Interactions: In Arabidopsis, Z-ISO mutants (e.g., ziso-155) disrupt plastid development unless combined with carotenoid cleavage dioxygenase (CCD) inhibitors, implicating apocarotenoid retrograde signals ( ).
Heterologous Complementation Studies
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Substrate Specificity: Recombinant Z-ISO expressed in E. coli confirmed exclusive activity on 9,15,9′-tri-cis-ζ-carotene, with no cross-reactivity on phytoene ( ).
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Mutant Rescue: Complementation of Synechocystis Δslr1599 (Z-ISO-deficient) restored carotenoid synthesis under darkness ( ).
Mechanistic Insights
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Heme Dependency: Spectroscopic studies confirmed heme B’s role in redox-mediated activation ( ).
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Structural Predictions: AlphaFold models identified conserved histidine residues (His-154, His-158 in maize) as putative heme ligands ( ).
Biotechnological Relevance
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Biofortification: Z-ISO is a target for enhancing provitamin A in crops like maize and rice ( ).
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Stress Adaptation: Modulates carotenoid flux under temperature fluctuations, impacting plant resilience ( ).
Comparative Analysis of Z-ISO Homologs
Challenges and Future Directions
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Structural Resolution: No crystallographic data exists; resolving Z-ISO’s 3D structure remains a priority ( ).
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Apocarotenoid Signaling: The role of Z-ISO-derived metabolites in plastid-nuclear communication requires further study ( ).
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Engineering Applications: Optimizing Z-ISO for high-yield carotenoid production in synthetic biology systems ( ).
Product Specs
Note: We will prioritize shipping the format currently in stock. However, if you have specific requirements for the format, please indicate them in your order notes. We will prepare the product according to your request.
Note: All our proteins are shipped with standard blue ice packs. If dry ice shipping is required, please inform us in advance, as additional fees will apply.
Generally, the shelf life of the liquid form is 6 months at -20°C/-80°C. The shelf life of the lyophilized form is 12 months at -20°C/-80°C.
Target Background
- As an isomerase, Z-ISO represents a novel prototype for heme b proteins and potentially utilizes a unique chemical mechanism. PMID: 26075523
