I am a microbial-molecular biologist, biotechnologist and natural product investigator with a research background in terpene cyclase enzyme and terpene biosynthesis from Actinobacteria. During my time in the lab, I’ve enjoyed applying my diverse technical skillset to research problems and implementing new methods. Read More
Identification, cloning, overexpression and characterization of putative terpene cyclase from Stackebrandtia nassauensis
The goal of the study was to partially establish the role of a putative terpene synthase gene (snas_1127) identified from a soil-dwelling Gram-positive, filamentous actinobacteria, Stackebrandtia nassauensis DSM 44728 by genome mining to be a functional germacradienol synthase enzyme. The snas_1127 gene of S. nassauensis was cloned by PCR and heterologously expressed in Escherichia coli as an N-terminal-His6-tag protein. Incubation of the recombinant protein, SNAS_1127, with farnesyl diphosphate (FPP) in the presence of Mg2+ gave a sesquiterpene germacradienol; a precursor for many industrially important terpene metabolites. However, the bioinformatics analysis revealed that the target protein contains two conserved domains, viz. C-terminal domain and N-terminal domain. It is already established that the C-terminal domain catalyzed the conversion of farnesyl pyrophosphate (FPP) to germacradienol and thus germacradienol serves as a substrate for the N-terminal domain and gets converted to geosmin. On manual comparison of the identified protein sequence with already characterized germacradienol/ geosmin synthases, it was observed that there is a point mutation in the NSE triad (274E instead of the usual 274D) of the N-terminal domain. This might be why SNGS catalyzed only the conversion of FPP to germacradien-4-ol, and due to point mutation, the further conversion didn’t go as expected. Therefore, no other identifiable products were observed on GC-MS. As SNGS catalyzed the conversion of FPP to germacradienol, which being the precursor for the synthesis of many industrially useful metabolites, can be synthesized in a controlled manner without the risk of further conversion by the N-terminal domain. PhD Research in a Bird-eye View