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Calmodulin inhibitors from Aspergillus stromatoides.
Martín González-Andrade1, Paulina Del Valle, Martha L Macías-Rubalcava
1Facultad de Química, Universidad Nacional Autónoma de México, México DF 04510, México.
Chemistry & Biodiversity
|March 16, 2013
Summary
Marine fungus Aspergillus stromatoides yielded emodin and ω-hydroxyemodin, potent calmodulin (CaM) inhibitors. These compounds exhibit concentration-dependent fluorescence quenching, outperforming the standard inhibitor chlorpromazine in binding affinity.
Area of Science:
- Natural product chemistry
- Biochemistry
- Molecular biology
Background:
- Marine fungi are a rich source of novel bioactive compounds.
- Calmodulin (CaM) is a crucial calcium-binding protein involved in numerous cellular processes.
- Identifying new CaM inhibitors can lead to therapeutic advancements.
Purpose of the Study:
- To isolate and characterize compounds from the marine fungus Aspergillus stromatoides.
- To evaluate the potential of these compounds as calmodulin (CaM) inhibitors.
- To investigate the binding mechanism of the identified CaM inhibitors.
Main Methods:
- Organic extraction and column chromatography for compound isolation.
- Fluorescence quenching assay using a calmodulin (CaM) biosensor (hCaM M124C-mBBr).
- Determination of inhibition constants (K(d)) and molecular docking analysis.
Main Results:
- Emodin (1) and ω-hydroxyemodin (2) were isolated and identified as CaM inhibitors.
- Compounds 1 and 2 demonstrated potent fluorescence quenching of the CaM biosensor with K(d) values of 0.33 μM and 0.76 μM, respectively.
- Docking studies indicated that compounds 1 and 2 bind to the same site as chlorpromazine (CPZ), a known CaM inhibitor.
Conclusions:
- Emodin and ω-hydroxyemodin are effective calmodulin (CaM) inhibitors with significant binding affinities.
- The identified compounds possess CaM inhibitory properties that correlate with their known biological activities.
- This study highlights the potential of marine fungi as a source for novel therapeutic agents targeting CaM.
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