Recombinant Nautilus macromphalus Uncharacterized protein SMPP2
Description
Functional and Evolutionary Context
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Biomineralization Role: SMPP2 is classified as a hydrophilic shell matrix protein, a group critical for regulating calcium carbonate crystallization in mollusk shells . Its aspartate- and glycine-rich sequence resembles motifs in other SMPs that bind calcium ions .
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Species Specificity: SMPP2 has not been identified in transcriptomic or proteomic studies of Nautilus pompilius, suggesting it may be unique to N. macromphalus .
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Evolutionary Implications: The lack of homology with SMPs in other conchiferans (e.g., Crassostrea gigas, Pinctada fucata) implies divergent molecular mechanisms in nautiloid shell formation .
Research Applications and Limitations
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Experimental Use: Recombinant SMPP2 is primarily utilized for antibody production, structural studies, and in vitro biomineralization assays .
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Knowledge Gaps:
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No peer-reviewed functional studies or in vivo localization data are available.
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The protein’s interaction partners and regulatory pathways in shell synthesis remain unknown.
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Future Directions
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Functional Characterization: In vitro crystallization assays to test SMPP2’s role in calcium carbonate nucleation.
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Comparative Proteomics: Screening other Nautilus species for SMPP2 homologs to assess its taxonomic distribution.
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Structural Analysis: X-ray crystallography or NMR to resolve its 3D conformation and active sites.
