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particular PKS is iterative or not.[3] Structural analysis of the active sites in the KS domain has given information about what features in the domain control the number of iterations required for the synthesis of a polyketide and the amino acids that come into play for this. This study suggests that the sequence of the KS domain encodes the structural features of the polyketide. It has also been mentioned in papers that the KS domains cluster into groups depending upon whether the corresponding type I PKS contains additional reductive domains or not.[3-5]Researchers have noticed a distinct difference in the hydrophobicity of the pocket and correlated it to the extent of unsaturation in the product. They found that the T-toxin cavity was more hydrophobic than the MSAS cavity since the earlier one was a reduced PKS while the latter, was a partially reduced PKS. They also showed that the cavity volume correlated positively to the number of iterations and divided the KS cavity volume into three groups; small, large and intermediate depending upon the number of iterations. These findings reveal how cavity volume and hydrophobicity direct the number of iterations and influence the length of the chain. They also showed how site residues of the domain direct iterations. Another study emphasized
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 17 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@lib.usc.edu |
| Full text | 11 particular PKS is iterative or not.[3] Structural analysis of the active sites in the KS domain has given information about what features in the domain control the number of iterations required for the synthesis of a polyketide and the amino acids that come into play for this. This study suggests that the sequence of the KS domain encodes the structural features of the polyketide. It has also been mentioned in papers that the KS domains cluster into groups depending upon whether the corresponding type I PKS contains additional reductive domains or not.[3-5]Researchers have noticed a distinct difference in the hydrophobicity of the pocket and correlated it to the extent of unsaturation in the product. They found that the T-toxin cavity was more hydrophobic than the MSAS cavity since the earlier one was a reduced PKS while the latter, was a partially reduced PKS. They also showed that the cavity volume correlated positively to the number of iterations and divided the KS cavity volume into three groups; small, large and intermediate depending upon the number of iterations. These findings reveal how cavity volume and hydrophobicity direct the number of iterations and influence the length of the chain. They also showed how site residues of the domain direct iterations. Another study emphasized |
