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Common features of the biosynthetic pathways of lincomycin,some pyrrolo-1,4-benzodiazepines and hormaomycin
Steiningerová, Lucie ; Janata, Jiří (advisor) ; Mašek, Tomáš (referee)
Lincosamides, pyrrolo-1,4-benzodiazepines (PBD) and hormaomycin are biologically active substances differing in their structure and mode of action. Lincosamides lincomycin and clindamycin are clinically used antibiotics, PBD exhibit antitumor activity and hormaomycin is a bacterial hormone. Unusual precursor, 4-propyl-L-proline (PPL) derived from L-tyrosine is incorporated in the lincomycin structure. Surprisingly, structurally and functionally dissimilar hormaomycin and some PBD (tomaymycin, anthramycin, sibiromycin) incorporate L-proline derivative with two- or three- carbon side chain of the same biosynthetic origin. Accordingly, a set of orthologous genes coding for biosynthesis of these structurally similar precursors has been found in appropriate biosynthetic gene clusters. There is a clear evolutionary relationship among the biosynthesis of lincomycin, hormaomycin and some PBD. However, the evolutionary origin of PPL pathway is not known as well as its further development. Only a limited number of naturally occured modifications of the pathway has been described and the history of supposed horizontal gene transfers of biosynthetic genes remains unknown. Answers to these questions are particularly important due to the preparation of new hybrid substances with improved bioactive effects using methods...
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Preparation and characterization of LmbX protein involved in lincomycin biosynthesis
Jiráčková, Petra ; Janata, Jiří (advisor) ; Janderová, Blanka (referee)
Lincomycin is an antibiotic used in clinical praxis. It is produced by Streptomyces lincolnensis. Lincomycin is composed of an amino-sugar and an amino-acid moiety linked by an amide bond. The amino-acid precursor is propylproline (PPL), whose biosynthesis undergoes the pathway derived from tyrosine. The modified PPL biosynthesis pathway was also discovered in pyrrolobenzodiazepines (PBD) and hormaomycin. In the biosynthesis of PBD the PPL precursor is further modified by reactions catalysed by specific enzymes missing in the biosynthesis of lincomycin. The genes encoding these enzymes could be transferred to the lincomycin biosynthetic gene cluster. In this way we could get producers of hybrid antibiotics with better properties and even antimalaric effects. Six enzymes participate in PPL biosynthesis, which are encoded in the lincomycin biosynthetic gene cluster. The first two reactions of PPL biosynthesis pathway are proven, therefore, this work focuses on the third reaction that is supposed to be catalysed by protein LmbX according to literature. The proposed function of LmbX is a hydrolysis of C-C bond. However, LmbX belongs to the protein family of isomerases by sequence homology. The protein LmbX was overproduced in this work and its activity was tested in the presence of the expected...
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