Abstract:Sterols are vital for nearly all eukaryotes. Their distribution differs in plants and animals, with phytosterols commonly found in plants whereas most animals are dominated by cholesterol. We show that sitosterol, a common sterol of plants, is the most abundant sterol in gutless marine annelids. Using multiomics, metabolite imaging, heterologous gene expression, and enzyme assays, we show that these animals synthesize sitosterol de novo using a noncanonical C-24 sterol methyltransferase (C
24
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“…The C. teleta SMT and one of the two P. dumerilii proteins appear more structurally similar to the bifunctional SMT2 than ERG6, as suggested by their lower RMSD scores, and is particularly noticeable in the alpha helices in the C-terminal domain. This supports recent results by Michellod et al demonstrating that SMTs of the annelids Olavius and Inanidrilus can bifunctionally generate C 28 and C 29 sterols 19 , and suggests this ability is commonplace across annelids. Fig.…”
Section: Resultssupporting
confidence: 91%
“…4 ). This functional analysis complements Michellod et al, demonstrating that multiple annelid species can methylate sterols 19 . Fig.…”
Section: Resultssupporting
confidence: 76%
“…Unlike sea sponges, annelid worms are part of the Eumetazoa, a clade of animals whose cell membranes are generally dominated by cholesterol, and who are thought to have lost the ability to make C 28+ sterols 7 , 18 . Since we began the study of smt in C. Teleta , another study by Michellod et al has demonstrated the synthesis of C 28/29 sterols in a different annelid, Olavius algarvensis , and reported smt genes in many animals 19 . The goal of this study is to determine the veracity of the C. teleta smt and reconstruct its evolutionary history.…”
Section: Introductionmentioning
confidence: 99%
“…Using yeast gene rescue experiments, we demonstrate that the C. teleta SMT protein is capable of synthesizing C 28 sterols, providing evidence that SMT function has been conserved through annelid evolution. Careful vetting of the animal smt tree supports vertical inheritance of the gene from a common ancestor, as opposed to inheritance via horizontal gene transfer 19 . Finally, we produce molecular clocks to demonstrate that a vertically inherited SMT was spreading through eumetazoans during the Neoproterozoic, with most lineages losing the gene around this time.…”
Steranes preserved in sedimentary rocks serve as molecular fossils, which are thought to record the expansion of eukaryote life through the Neoproterozoic Era ( ~ 1000-541 Ma). Scientists hypothesize that ancient C27 steranes originated from cholesterol, the major sterol produced by living red algae and animals. Similarly, C28 and C29 steranes are thought to be derived from the sterols of prehistoric fungi, green algae, and other microbial eukaryotes. However, recent work on annelid worms–an advanced group of eumetazoan animals–shows that they are also capable of producing C28 and C29 sterols. In this paper, we explore the evolutionary history of the 24-C sterol methyltransferase (smt) gene in animals, which is required to make C28+ sterols. We find evidence that the smt gene was vertically inherited through animals, suggesting early eumetazoans were capable of C28+ sterol synthesis. Our molecular clock of the animal smt gene demonstrates that its diversification coincides with the rise of C28 and C29 steranes in the Neoproterozoic. This study supports the hypothesis that early eumetazoans were capable of making C28+ sterols and that many animal lineages independently abandoned its biosynthesis around the end-Neoproterozoic, coinciding with the rise of abundant eukaryotic prey.
“…The C. teleta SMT and one of the two P. dumerilii proteins appear more structurally similar to the bifunctional SMT2 than ERG6, as suggested by their lower RMSD scores, and is particularly noticeable in the alpha helices in the C-terminal domain. This supports recent results by Michellod et al demonstrating that SMTs of the annelids Olavius and Inanidrilus can bifunctionally generate C 28 and C 29 sterols 19 , and suggests this ability is commonplace across annelids. Fig.…”
Section: Resultssupporting
confidence: 91%
“…4 ). This functional analysis complements Michellod et al, demonstrating that multiple annelid species can methylate sterols 19 . Fig.…”
Section: Resultssupporting
confidence: 76%
“…Unlike sea sponges, annelid worms are part of the Eumetazoa, a clade of animals whose cell membranes are generally dominated by cholesterol, and who are thought to have lost the ability to make C 28+ sterols 7 , 18 . Since we began the study of smt in C. Teleta , another study by Michellod et al has demonstrated the synthesis of C 28/29 sterols in a different annelid, Olavius algarvensis , and reported smt genes in many animals 19 . The goal of this study is to determine the veracity of the C. teleta smt and reconstruct its evolutionary history.…”
Section: Introductionmentioning
confidence: 99%
“…Using yeast gene rescue experiments, we demonstrate that the C. teleta SMT protein is capable of synthesizing C 28 sterols, providing evidence that SMT function has been conserved through annelid evolution. Careful vetting of the animal smt tree supports vertical inheritance of the gene from a common ancestor, as opposed to inheritance via horizontal gene transfer 19 . Finally, we produce molecular clocks to demonstrate that a vertically inherited SMT was spreading through eumetazoans during the Neoproterozoic, with most lineages losing the gene around this time.…”
Steranes preserved in sedimentary rocks serve as molecular fossils, which are thought to record the expansion of eukaryote life through the Neoproterozoic Era ( ~ 1000-541 Ma). Scientists hypothesize that ancient C27 steranes originated from cholesterol, the major sterol produced by living red algae and animals. Similarly, C28 and C29 steranes are thought to be derived from the sterols of prehistoric fungi, green algae, and other microbial eukaryotes. However, recent work on annelid worms–an advanced group of eumetazoan animals–shows that they are also capable of producing C28 and C29 sterols. In this paper, we explore the evolutionary history of the 24-C sterol methyltransferase (smt) gene in animals, which is required to make C28+ sterols. We find evidence that the smt gene was vertically inherited through animals, suggesting early eumetazoans were capable of C28+ sterol synthesis. Our molecular clock of the animal smt gene demonstrates that its diversification coincides with the rise of C28 and C29 steranes in the Neoproterozoic. This study supports the hypothesis that early eumetazoans were capable of making C28+ sterols and that many animal lineages independently abandoned its biosynthesis around the end-Neoproterozoic, coinciding with the rise of abundant eukaryotic prey.
“…148,149 Furthermore, Liebeke and coworkers found that gutless marine annelids predominantly synthesized sitosterol, a plant sterol, by a noncanonical SMT, indicating the broader occurrence of plant-like sterol biosynthesis in animals. 150,151…”
Steroids are an important family of bioactive compounds. Steroid drugs are renowned for their multifaceted pharmacological activities and are the second-largest category in the global pharmaceutical market. Recent developments in...
Phytosterols usually have to be esterified to various phytosterol esters to avoid their disadvantages of unsatisfactory solubility and low bioavailability. The enzymatic synthesis of phytosterol esters in a solvent‐free system has advantages in terms of environmental friendliness, sustainability, and selectivity. However, the limitation of the low stability and recyclability of the lipase in the solvent‐free system, which often requires a relatively high temperature to induce the viscosity, also increased the industrial production cost. In this context, a low‐cost material, namely diatomite, was employed as the support in the immobilization of Candida rugosa lipase (CRL) due to its multiple modification sites. The Fe3O4 was also then introduced to this system for quick and simple separation via the magnetic field. Moreover, to further enhance the immobilization efficiency of diatomite, a modification strategy which involved the octadecyl and sulfonyl group for regulating the hydrophobicity and interaction between the support and lipase was successfully developed. The optimization of the ratio of the modifiers suggested that the ‐SO3H/C18 (1:1.5) performed best with an enzyme loading and enzyme activity of 84.8 mg·g−1 and 54 U·g−1, respectively. Compared with free CRL, the thermal and storage stability of CRL@OSMD was significantly improved, which lays the foundation for the catalytic synthesis of phytosterol esters in solvent‐free systems. Fortunately, a yield of 95.0% was achieved after optimizing the reaction conditions, and a yield of 70.0% can still be maintained after six cycles.
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