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B] The second method for the release of the final product is the use of PLP dependent mechanism observed in the biosynthesis of fumonisinsin F. erticil- lioides. Experiments showed that the 2-oxoamine synthase encoded by FUM8 was responsible for off-loading the final product of fumonisin, elongating the carbon backbone as well as introducing the amine group in fumonisin. Two enzyme encoding genes played an important role in the biosynthesis of fumonisin, FUM8 and FUM1. FUM1 was predicted to encode a seven-domain PKS (Fum1p, 2507residues), whereas FUM8 was predicted to encode a protein (Fum8p, 839residues) that is homologous to L serine palmitoyl transferase (SPT), which is a member of the 2-oxo amine synthase family. PLP is used by these enzymes as a cofactor to catalyze the decarboxylative condensation between an amino acid and a acyl-CoA. The function of the PLP dependent FUM8 was studied in yeast to determine whether the combination of PLP and FUM8 led to the release of fumonisin. First the ACP of FUM1 was expressed and purified from E.coli for in vitro studies. An acyl chain was then loaded on to the ACP and the acylation of the phosphopantetheine arm of ACP was confirmed. The next step consisted of expressing FUM8 in yeast INVSc1 and then preparing microsomes out of those cells. Two types of microsomes were prepared, one containing
Object Description
| Title | Fungal polyketides -- Review of recent findings |
| Author | Jain, Sofina M. |
| Author email | sofinaja@usc.edu; sofinajain27@gmail.com |
| Degree | Master of Science |
| Document type | Thesis |
| Degree program | Pharmacy / Pharmaceutical Sciences |
| School | School of Pharmacy |
| Date defended/completed | 2011-05-04 |
| Date submitted | 2011 |
| Restricted until | Unrestricted |
| Date published | 2011-05-05 |
| Advisor (committee chair) | Wang, Clay C. C. |
| Advisor (committee member) |
Okamoto, Curtis Toshio Shen, Wei-Chiang |
| Abstract | Fungal polyketides are a group of bioactive compounds which have found use in humans as anti-cholesterol, anti-cancer and antibiotic agents. These are synthesized by a group of enzymes called the polyketide synthases (PKSs) which are found in fungi as well as bacteria. PKSs are classified as type I, II and III. All fungal PKSs are type I iterative polyketide synthases which means they use a set of catalytic functions by a group of active domains in repetitive cycles to give the end product. Type I enzymes contain multidomains that catalyze a set of reactions.; The minimal PKS contains the domains ketosynthase (KS), acyltransferase (AT) and acyl carrier protein (ACP). The three types of PKSs are non-reduced polyketide synthases (NR-PKSs), highly-reduced polyketide synthases (HR-PKSs) and partially-reduced polyketide synthases (PR-PKSs). This classification is another form separate from type I, II and III. This paper discusses the recent research into further details of the SAT, PT and TE domain of the NR-PKSs and also recent advances in the HR-PKSs. This paper will also discuss the role of NADPH, SAM and CON domain in the HR-PKSs. We will also discuss the two off-loading mechanism of HR-PKSs that were seen in recent papers. While little research is done on PR-PKSs, NR-PKS and HR-PKS are extensively being worked on.Recent findings have brought us a step closer to the domains of the PKSs and promise us a better clearer understanding of this complex multidomain entity. |
| Keyword | fungal polyketides; HR-PKS; NR-PKS; PT domain; SAT domain; TE domain |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Provenance | Electronically uploaded by the author |
| Type | texts |
| Legacy record ID | usctheses-m3914 |
| Contributing entity | University of Southern California |
| Rights | Jain, Sofina M. |
| Repository name | Libraries, University of Southern California |
| Repository address | Los Angeles, California |
| Repository email | cisadmin@lib.usc.edu |
| Filename | etd-jain-4552 |
| Archival file | uscthesesreloadpub_Volume40/etd-jain-4552.pdf |
Description
| Title | Page 54 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@lib.usc.edu |
| Full text | 48 B] The second method for the release of the final product is the use of PLP dependent mechanism observed in the biosynthesis of fumonisinsin F. erticil- lioides. Experiments showed that the 2-oxoamine synthase encoded by FUM8 was responsible for off-loading the final product of fumonisin, elongating the carbon backbone as well as introducing the amine group in fumonisin. Two enzyme encoding genes played an important role in the biosynthesis of fumonisin, FUM8 and FUM1. FUM1 was predicted to encode a seven-domain PKS (Fum1p, 2507residues), whereas FUM8 was predicted to encode a protein (Fum8p, 839residues) that is homologous to L serine palmitoyl transferase (SPT), which is a member of the 2-oxo amine synthase family. PLP is used by these enzymes as a cofactor to catalyze the decarboxylative condensation between an amino acid and a acyl-CoA. The function of the PLP dependent FUM8 was studied in yeast to determine whether the combination of PLP and FUM8 led to the release of fumonisin. First the ACP of FUM1 was expressed and purified from E.coli for in vitro studies. An acyl chain was then loaded on to the ACP and the acylation of the phosphopantetheine arm of ACP was confirmed. The next step consisted of expressing FUM8 in yeast INVSc1 and then preparing microsomes out of those cells. Two types of microsomes were prepared, one containing |
