Clc genomics workbench duke5/3/2023 Each module is used only once during polyketide assembly, thus the architecture of each module influences the overall polyketide structure. In contrast, modular Type I PKS function in a conveyor belt like manner in that the different catalytic domains are organized in modules comprising all required enzymatic functions. Fungal iterative Type I PKSs use the same set of catalytic domains on one protein several times for chain extension, analogously to vertebrate FAS. Type I PKS are large multifunctional proteins which combine several domains in one protein. PKS are traditionally classified into three types. Beyond that, the presence of ketoacylreductase (KR), dehydrases (DH) and enoylreductases (ER) may lead to a stepwise reduction of keto-groups and thus contribute to the vast variety of polyketide structure. In general, PKS require a minimum set of catalytic domains which are ketoacylsynthase (KS), acyl transferase (AT) and acyl carrier protein (ACP) for one round of chain extension. PKS are large multi-domain enzyme complexes which resemble fatty synthases (FAS) both in structure and function and most probably also share a common origin with the latter. The diverse and complex structures of these compounds are assembled through repetitive condensation and reduction steps of simple acyl monomers through polyketide synthases (PKS). Polyketides are a structurally diverse class of secondary metabolites with various potential biomedical or pharmaceutical applications as antibiotics, insecticides, immunosurpressive and anti-tumor agents. Dinoflagellates produce a wide variety of most likely polyketide synthesis derived secondary metabolites among which several well described phycotoxins can elicit life-threating symptoms in humans –. Apart from that, some of them are the major causative agents for red tides and harmful algal blooms (HAB) in marine environments. They also play a crucial role in structuring microbial plankton communities due to their auto- and heterotrophic or even parasitic life styles. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Ĭompeting interests: The authors have declared that no competing interests exist.ĭinoflagellates are among the most important primary producers and therefore are important drivers of marine food webs. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.įunding: Financial support was provided by the PACES research program of the Alfred Wegener Institute, within the Helmholtz Foundation Initiative in Earth and Environment. Received: JAccepted: OctoPublished: November 5, 2012Ĭopyright: © 2012 Eichholz et al. We discuss the implications of this novel region with regard to the putative monofunctional organization of Type I PKS in dinoflagellates.Ĭitation: Eichholz K, Beszteri B, John U (2012) Putative Monofunctional Type I Polyketide Synthase Units: A Dinoflagellate-Specific Feature? PLoS ONE 7(11):ĭuke University Medical Center, Duke University, United States of America In addition, the sequenced transcripts harbored a previously unknown, apparently dinoflagellate specific conserved N-terminal domain. These findings indicate that the atypical PKS I structure, i.e., expression as putative monofunctional units, might be a dinoflagellate specific feature. In a maximum likelihood phylogenetic analysis of KS domains from diverse PKSs, dinoflagellate KSs formed a clade placed well within the protist Type I PKS clade between apicomplexa, haptophytes and chlorophytes. The monofunctional structure was also confirmed using dinoflagellate specific KS antibodies in Western Blots. Each of the five transcripts encoded a single ketoacylsynthase (KS) domain showing high similarity to K. The five full length transcripts we obtained were all characterized by polyadenylation, a 3′ UTR and the dinoflagellate specific spliced leader sequence at the 5′end. Here, we investigated expression units of PKS I-like sequences in Alexandrium ostenfeldii (gonyaulacales) and Heterocapsa triquetra (peridiniales) at the transcript and protein level. Recently, novel polyketide synthesase (PKS) transcripts have been described from the Florida red tide dinoflagellate Karenia brevis (gymnodiniales) which are evolutionarily related to Type I PKS but were apparently expressed as monofunctional proteins, a feature typical of Type II PKS. Marine dinoflagellates (alveolata) are microalgae of which some cause harmful algal blooms and produce a broad variety of most likely polyketide synthesis derived phycotoxins.
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