Syarul Nataqain Baharum

Functional Characterisation of New Sesquiterpene Synthase from the Malaysian Herbal Plant, Polygonum Minus

Polygonum minus (syn. Persicaria minor) is a herbal plant that is well known for producing sesquiterpenes, which contribute to its flavour and fragrance. This study describes the cloning and functional characterisation of PmSTPS1 and PmSTPS2, two sesquiterpene synthase genes that were identified from P. minus transcriptome data mining. The full-length sequences of the PmSTPS1 and PmSTPS2 genes were expressed in the E. coli pQE-2 expression vector. The sizes of PmSTPS1 and PmSTPS2 were 1098 bp and 1967 bp, respectively, with open reading frames (ORF) of 1047 and 1695 bp and encoding polypeptides of 348 and 564 amino acids, respectively. The proteins consist of three conserved motifs, namely, Asp-rich substrate binding (DDxxD), metal binding residues (NSE/DTE), and cytoplasmic ER retention (RxR), as well as the terpene synthase family N-terminal domain and C-terminal metal-binding domain. From the in vitro enzyme assays, using the farnesyl pyrophosphate (FPP) substrate, the PmSTPS1 enzyme produced multiple acyclic sesquiterpenes of β-farnesene, α-farnesene, and farnesol, while the PmSTPS2 enzyme produced an additional nerolidol as a final product. The results confirmed the roles of PmSTPS1 and PmSTPS2 in the biosynthesis pathway of P. minus, to produce aromatic sesquiterpenes.

Metabolomics data of Mitragyna speciosa leaf using LC-ESI-TOF-MS

Mitragyna speciosa is a psychoactive plant known as “ketum” in Malaysia and “kratom” in Thailand. This plant is distinctly known to produce two important alkaloids, namely mitragynine (MG) and 7-hydroxymitragynine (7-OH-MG) that can bind to opioid receptors [1]. MG was reported to exhibit antidepressant properties in animal studies [2]. These compounds were also proposed to have the potential to replace opioid analgesics with much lower risks of side effects [3]. To date, there are only over 40 metabolites identified in M. speciosa [4,5]. To obtain a more complete profile of secondary metabolites in ketum, we performed metabolomics study using mature leaves of the green M. speciosa variety. The leaf samples were extracted using methanol prior to liquid chromatography-electrospray ionization-time of flight-mass spectrometry (LC-ESI-TOF-MS) analysis. This data can be useful to for the identification of unknown metabolites that are associated with alkaloid biosynthesis pathway in M. speciosa.

Metabolomics Study in Methylotrophic Yeast: A Minireview

Methylotrophic yeast has been used as a cost-effective and valuable host for expression of recombinant protein due to its unique methanol utilisation pathway. It has an AOX (alcohol oxidase) protein which has been characterised to be a strong and tightly methanol-inducible dependent promoter. Metabolomics is the systematic study and inclusive analysis of small molecules called metabolites in a biological system. Metabolomics plays an important part in connecting the phenotype and genotype gap because it magnifies the modifications in the proteome and provides a better phenotype representation of an organism. This quantitative study has provided a new perception on the metabolic burden derived from the overexpression of recombinant protein in methylotrophic yeast. In this review, we discuss the fundamental aspect of metabolomics in methylotrophic yeast followed by their latest developments.