Research reveals the evolutionary origin of camptothecin biosynthesis pathway

Research reveals the evolutionary origin of camptothecin biosynthesis pathway

Research reveals the evolutionary origin of camptothecin synthesis pathway Research reveals the evolutionary origin of camptothecin synthesis pathway

Recently, the research group of Professor Liu Jianquan of the School of Life Sciences of Sichuan University published online research results in the journal Nature Communications, revealing the evolutionary origin of camptothecin synthesis pathways in Camptotheca acuminata
.

Camptotheca acuminata (also known as Qianzhang tree) is mainly distributed in the mountains of southwest China.
Because of its fast growth, it is also widely used as a tree species for greening and street trees.
It is widely planted in university campuses, streets and various living areas in the south
.

Camptothecin (Camptothecin) is a new type of anti-tumor monoterpene indole alkaloid.

Due to its high medicinal and economic value, the biosynthesis and chemical synthesis of camptothecin and its derivatives have become a hot and difficult problem in recent years
.

Previous studies on camptothecin biosynthesis in camptothecin are mainly based on the transcriptome, lack of high-quality genome sequence and identification of related genes, and the synthesis pathway of camptothecin and its origin and evolution are still unclear, which limits efficient artificial biosynthesis.

In order to solve this problem, Liu Jianquan’s research team first assembled and annotated a high-quality chromosome-level Camptotheca acuminata genome through PacBio and HiC technology, which was superior to the previously published second Illumina platform-based Illumina platform in terms of assembly accuracy, continuity, and gene annotation quality.
Generation non-chromosomal genome version, gene annotation completeness is also significantly higher than the previous non-parametric transcriptome version
.

Then the phylogenetic tree construction, differentiation time estimation, and genome-wide doubling event analysis showed that: in addition to the ancient doubling event shared with grapes, after diverging from other neighboring taxa about 107 million years ago, Camptotheca acuminata had a growth rate of about 70%.

In order to further study the evolution of camptothecin biosynthetic pathways in camptothecin, the researchers first identified a more complete set of candidate genes related to camptothecin synthesis based on gene function annotation and gene family analysis, including cells that may be related to subsequent synthesis steps.
Color P450 (CYP450) enzyme family coding genes and their subfamily classification
.

Using previously published multi-tissue transcriptome data, the expression levels of candidate genes were calculated and co-expression network analysis was performed.

Catharanthus roseus

In order to study the molecular mechanism of this evolutionary divergence, the researchers first simulated the three-dimensional structure of the loganine acid methyltransferase protein in Camptotheca acuminata, and compared it with the loganine acid methyltransferase of Catharanthus roseus and found that Camptotheca acuminata The mutations in the key sites associated with loganylic acid binding, which are unique in the moneyylic acid methyltransferase, may result in the reduction of binding-related hydrogen bonds and the inability to stably bind to the substrate
.

In order to verify this, the researchers conducted mutation sequence construction, yeast expression and enzyme activity assays for these sites, and found that these mutations that bind to related sites would indeed seriously reduce or destroy the activity of loganyl acid methyltransferase
.

In addition, the two sever loganic acid synthase in Camptotheca acuminata have been proved to have both the activity of sever loganic acid synthase and sever loganic acid synthase in previous studies, and combine with other species of sever loganic acid synthase.

This study revealed the possible molecular evolutionary mechanism of camptothecin biosynthesis pathway in Camptotheca acuminata, and found that high-quality genome assembly plays a key role in identifying genetic changes in the evolutionary origin of new secondary metabolites
.

The high-quality set of pathway-related candidate genes also provides the basis for future artificial biosynthesis with fewer steps, low cost, and high yield

The research was mainly completed under the funding of the Pilot Program of the Chinese Academy of Sciences, the National Key Research and Development Program and the National Natural Science Foundation of China
.

(Source: China Science News Zhang Qingdan)

Related paper information: https://doi.

https://doi.
org/10.
1038/s41467-021-23872-9