Understanding a Unique Enzyme from Cordyceps for Healthier Fat Processing

Jim Crocker
21st July, 2024

Understanding a Unique Enzyme from Cordyceps for Healthier Fat Processing

Cordyceps militaris

Photo adapted from: Lukas Large / CC BY (Source)

Key Findings

  • Researchers at Seoul National University discovered a new lipase, CACML7, from Cordyceps militaris with sn-2 regioselectivity
  • CACML7 shows a unique preference for cis-fatty acids over trans-fatty acids, unlike other known lipases
  • The study highlights the potential of computational methods to find novel enzymes with specific and valuable properties for industrial applications
Lipases are enzymes that play a crucial role in lipid metabolism by breaking down fats into their constituent parts. They are highly valued in the food and pharmaceutical industries for their ability to modify lipids in specific ways. One of the key features that make certain lipases particularly valuable is their regioselectivity, which refers to their preference for acting on specific positions within the lipid molecule. The lipase from Candida antarctica (CALA) is well-known for its sn-2 regioselectivity, meaning it preferentially hydrolyzes the fatty acid at the second position on the glycerol backbone[1]. A recent study conducted by researchers at Seoul National University has identified a novel lipase from Cordyceps militaris, named CACML7, which also exhibits sn-2 regioselectivity. This discovery is significant because sn-2 regioselective lipases are rare in nature, and finding new ones can enhance our ability to modify lipids for various applications. The researchers utilized in silico mining, a computational method to search for genes encoding lipases with similar characteristics to CALA. They identified CACML7 and conducted a series of experiments to characterize its properties. Using chiral-phase high-performance liquid chromatography (HPLC), they confirmed that CACML7 has a high sn-2 regioselectivity, similar to CALA, but with some unique features. CACML7 was found to have a distinctive chain length selectivity and a bias against unsaturated fats. Specifically, it showed a 2.2-fold higher preference for cis-fatty acid (C18:1, cis-Δ9) over trans-fatty acid (C18:1, trans-Δ9), which is different from the trans-active CALA. This preference is believed to be due to the unique morphology of the active site in CACML7, described as an "acyl-binding tunnel with a narrow entrance." This structural feature likely contributes to its sn-2 regioselectivity by favoring the binding of the reactive ester group in the sn-2 position. The researchers also performed random pose docking of trioleoylglycerol (TOG) into the active site of a lid-truncated mutant of CACML7. This analysis revealed that TOG adopts a tuning fork conformation, positioning the reactive ester group favorably towards the catalytic center only via the sn-2 binding mode. This finding provides a model to better understand the mechanism underlying sn-2 regioselectivity. The discovery of CACML7 adds to the growing body of knowledge about lipases and their specificities. Previous studies have shown that lipases can have various regioselectivities and preferences. For example, a study on lipase from Pseudomonas fluorescens (PFL) demonstrated its selectivity for hydrolyzing trioleoylglycerol (TOG) in the order of sn-1, sn-2, and sn-3 positions, with a preference for 2,3-sn-diacylglycerol (DOG) over 1,2-sn-DOG[2]. Another study on adipose triglyceride lipase (ATGL) showed a strong preference for hydrolyzing long-chain fatty acid esters at the sn-2 position, which broadens to the sn-1 position upon stimulation by its co-activator CGI-58[3]. The identification of CACML7 not only expands the repertoire of known sn-2 regioselective lipases but also highlights the potential for discovering novel enzymes with unique properties through computational methods. This can pave the way for the development of new biocatalysts for lipid modification, which can be used in the production of structured lipids (SLs) with specific functional characteristics, such as ease of absorption, low calories, and reduced serum triglycerides[4]. The Lipase Engineering Database (LED) has been instrumental in classifying and understanding the diversity of lipases. The database integrates information on the sequence, structure, and function of lipases, esterases, and related proteins, and has been used to classify highly divergent lipases like CALA[5]. The updated release of the LED provides valuable tools for the systematic analysis of lipases, which can aid in the discovery and characterization of novel enzymes like CACML7. In summary, the discovery of the CACML7 lipase from Cordyceps militaris by researchers at Seoul National University represents a significant advancement in the field of lipid modification. Its unique sn-2 regioselectivity and preference for cis-fatty acids make it a valuable biocatalyst for various industrial applications. This study also underscores the importance of computational methods and databases in uncovering new enzymes with desirable properties.

BiotechBiochemMycology

References

Main Study

1) A sn-2 regioselective lipase with cis-fatty acid preference from Cordyceps militaris: Biochemical characterization and insights into its regioselective mechanism.

Published 18th July, 2024

https://doi.org/10.1016/j.ijbiomac.2024.134013

Related Studies

2) Direct and simultaneous analysis of lipase-catalyzed hydrolysis of high-oleic oil model by chiral stationary phase HPLC-ELSD.

https://doi.org/10.1016/j.foodchem.2021.130750

3) Studies on the substrate and stereo/regioselectivity of adipose triglyceride lipase, hormone-sensitive lipase, and diacylglycerol-O-acyltransferases.

https://doi.org/10.1074/jbc.M112.400416

4) Future of Structured Lipids: Enzymatic Synthesis and Their New Applications in Food Systems.

https://doi.org/10.3390/foods11162400

5) Structural classification by the Lipase Engineering Database: a case study of Candida antarctica lipase A.

https://doi.org/10.1186/1471-2164-11-123


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