MESing around with a primula obconica type III polyketide synthase
| dc.contributor.author | McDonald, Kyle | |
| dc.contributor.examiningcommittee | Whyard, Steve (Biological Sciences) | |
| dc.contributor.examiningcommittee | Jeffries, Kenneth (Biological Sciences) | |
| dc.contributor.supervisor | Stout, Jason | |
| dc.date.accessioned | 2023-07-19T20:19:33Z | |
| dc.date.available | 2023-07-19T20:19:33Z | |
| dc.date.issued | 2023-06-22 | |
| dc.date.submitted | 2023-06-22T23:29:01Z | en_US |
| dc.degree.discipline | Biological Sciences | en_US |
| dc.degree.level | Master of Science (M.Sc.) | |
| dc.description.abstract | Polyketide-derived compounds are key components of many pharmacologically relevant molecules; plants are a major source of polyketides and produce them using type III polyketide synthases (PKS). This research project investigates the role of a putative type III PKS (PoPKS) and a putative polyketide cyclase (PKC; PoDABB) in the biosynthesis of the benzoquinone primin produced by Primula obconica (primula). I hypothesized that primula uses these enzymes to produce olivetolic acid, which is further modified to primin in planta. Using heterologously expressed protein, the function of PoPKS and PoDABB were assayed in vitro and compared to that of a functionally similar type III PKS and PKC from Cannabis sativa, CsTKS and CsOAC. I was able to demonstrate that, like CsTKS, PoPKS is a type III PKS and is able to catalyze the synthesis of a triketide lactone, tetraketide lactone, and a linear tetraketide. PoDABB did not show any PKC activity but did increase the catalytic activity of PoPKS, suggesting that the protein may have another role in the primin pathway in planta. Interactions between the commonly used buffer MES and type III PKSs were observed that altered the activity of both PoPKS and CsTKS, allowing the enzymes to catalyze additional extension steps. An investigation of the compounds produced in the MES buffer systems suggest that PoPKS is able to catalyze the synthesis of pentaketide and hexaketide products as well as catalyze the cyclization of resorcylic acids, including olivetolic acid, without the need for a PKC. A homology model of PoPKS was developed and used to predict a novel type III PKS hydrogen binding network used to catalyze the release of a linear polyketide free acid; a tyrosine residue in this network may also participate in the cyclization of resorcylic acids. | |
| dc.description.note | October 2023 | |
| dc.identifier.uri | http://hdl.handle.net/1993/37422 | |
| dc.language.iso | eng | |
| dc.rights | open access | en_US |
| dc.subject | type III polyketide synthase | |
| dc.subject | primula obconica | |
| dc.subject | natural products | |
| dc.subject | Mes buffer | |
| dc.subject | resorcylic acid | |
| dc.title | MESing around with a primula obconica type III polyketide synthase | |
| dc.type | master thesis | en_US |
| local.subject.manitoba | no |