TY  - THES
T1  - Studies on the biosynthesis and heterologous expression of complex secondary metabolites from streptomycetes
A1  - Binz,Tina Maria
Y1  - 2009/05/11
N2  - The heterologous expression of natural product biosynthetic pathways is of increasing interest in biotechnology and drug discovery. This approach enables the production of complex metabolites in more amenable host organisms and provides the basis for the generation of novel analogs through genetic engineering. In this thesis, we describe a straightforward strategy for the heterologous expression of the highly complex phenalinolactone biosynthetic pathway, which was recently cloned from Streptomyces sp. Tü6071. Using Red/ET recombineering, the phenalinolactone pathway was reconstituted from two cosmids and heterologously expressed in several Streptomyces strains. The established expression system now provides a convenient platform for functional investigations of the biosynthetic genes and the generation of novel analogs, by genetic engineering of the pathway in Escherichia coli.
The second part of this thesis describes work on a distinct class of secondary metabolites, the GE81112 tetrapeptide family. We developed a strategy for the cloning and identification of the GE81112 biosynthetic gene cluster, in order to investigate the biosynthetic pathway in detail. Generation of a cosmid library enabled us to identify the corresponding biosynthetic gene cluster on two overlapping cosmids. In parallel, we established methods to manipulate the strain genetically, allowing us to verify the identity of the GE81112 gene cluster by gene inactivation experiments. In addition, we characterized several proteins from the pathway using enzymatic assays in vitro. Taken together, these data have enabled us to propose a preliminary model for GE81112 biosynthesis. The results also open the door to developing new derivatives of these promising compounds by genetic engineering. 

KW  - Streptomycetaceae
KW  - Antibiotikum
KW  - Heterologe Genexpression
KW  - Gencluster
CY  - Saarbrücken
PB  - Universitäts- und Landesbibliothek
AD  - Postfach 151141, 66041 Saarbrücken
UR  - http://scidok.sulb.uni-saarland.de/volltexte/2009/2145
ER  -