[cis-Prenyltransferases of Marchantia polymorpha: Phylogenetic Analysis and Perspectives for Use as Regulators of Antimicrobial Agent Synthesis]

The synthesis of secondary metabolites plays a central role in the survival of plants and their resistance to biotic and abiotic stress. Nevertheless, fundamental and applied studies of plant secondary metabolites, polyisoprenols, remain underdeveloped. The wide distribution of polyisoprenols in plants shows their important role in cellular metabolism. Plant polyisoprenols are synthesized by cis-prenyltransferases (CPTs), the study of which is necessary to understand the synthesis pathways, localization, and functions of plant polyisoprenols. Bryophytes, including the liverwort Marchantia polymorpha, are a unique group of plants with great potential for the study of CPTs. We analyzed the genome of M. polymorpha and identified seven CPT genes, which are homologous to the AtCPT7 and AtCPT3 genes of Arabidopsis thaliana, involved in the synthesis of polyisoprenols. Four individual lines of M. polymorpha plants with mutations in the MpCPT7.37 gene were obtained. It was shown that in three lines the mutation led to a translational frameshift and gene knockout. However, knockout of only the type 7 CPTs had no effect on plant growth and survival. Analysis of the antibacterial activity of mutant plant tissue extracts did not reveal significant changes compared to wild-type tissue extracts, this could be related to a compensatory effect of the activity of other CPTs. These data give us the required base for the further studies of bryophytes CPTs and their products.

Discovery of Prenyltransferase Inhibitors with In Vitro and In Vivo Antibacterial Activity

Cis-prenyltransferases such as undecaprenyl diphosphate synthase (UPPS) and decaprenyl diphosphate synthase (DPPS) are essential enzymes in bacteria and are involved in cell wall biosynthesis. UPPS and DPPS are absent in the human genome, so they are of interest as targets for antibiotic development. Here, we screened a library of 750 compounds from National Cancer Institute Diversity Set V for the inhibition of Mycobacterium tuberculosis DPPS and found 17 hits, and then IC₅₀s were determined using dose-response curves. Compounds were tested for growth inhibition against a panel of bacteria, for in vivo activity in a Staphylococcus aureus/Caenorhabditis elegans model, and for mammalian cell toxicity. The most active DPPS inhibitor was the dicarboxylic acid redoxal (compound 10), which also inhibited undecaprenyl diphosphate synthase (UPPS) as well as farnesyl diphosphate synthase. 10 was active against S. aureus, Clostridiodes difficile, Bacillus anthracis Sterne, and Bacillus subtilis, and there was a 3.4-fold increase in IC₅₀ on addition of a rescue agent, undecaprenyl monophosphate. We found that 10 was also a weak protonophore uncoupler, leading to the idea that it targets both isoprenoid biosynthesis and the proton motive force. In an S. aureus/C. elegans in vivo model, 10 reduced the S. aureus burden 3 times more effectively than did ampicillin.

cis-Prenyltransferase interacts with a Nogo-B receptor homolog for dolichol biosynthesis in Panax ginseng Meyer

Background

Prenyltransferases catalyze the sequential addition of isopentenyl diphosphate units to allylic prenyl diphosphate acceptors and are classified as either trans-prenyltransferases (TPTs) or cis-prenyltransferases (CPTs). The functions of CPTs have been well characterized in bacteria, yeast, and mammals compared to plants. The characterization of CPTs also has been less studied than TPTs. In the present study, molecular cloning and functional characterization of a CPT from a medicinal plant, Panax ginseng Mayer were addressed.

Methods

Gene expression patterns of PgCPT1 were analyzed by quantitative reverse transcription polymerase chain reaction. In planta transformation was generated by floral dipping using Agrobacterium tumefaciens. Yeast transformation was performed by lithium acetate and heat-shock for rer2Δ complementation and yeast-two-hybrid assay.

Results

The ginseng genome contains at least one family of three putative CPT genes. PgCPT1 is expressed in all organs, but more predominantly in the leaves. Overexpression of PgCPT1 did not show any plant growth defect, and its protein can complement yeast mutant rer2Δ via possible protein–protein interaction with PgCPTL2.

Conclusion

Partial complementation of the yeast dolichol biosynthesis mutant rer2Δ suggested that PgCPT1 is involved in dolichol biosynthesis. Direct protein interaction between PgCPT1 and a human Nogo-B receptor homolog suggests that PgCPT1 requires an accessory component for proper function.