In-planta Analysen der drei Arabidopsis Isoformen des bifunktionalen RIBA Proteins mit katalytischen Domänen für GTP Cyclohydrolase II und 3,4-Dihydroxy-2-Butanon-4-Phosphat-Synthase
Zusammenfassung der Projektergebnisse
Only little information is available on biochemistry and control of plant riboflavin metabolism. Riboflavin serves as precursor for flavor-coenzymes (FMN and FAD) and is essential for all living organisms. By means of the proposed working program it was aimed to verify the function of the three bi-functional RIBA isoforms in riboflavin biosynthesis, which catalyze the initial two committed enzymatic steps of riboflavin biosynthesis in plants (a GTP cyclo-hydrolase II (GCHII) and 3,4-dihydroxy-2-butanone-4-phosphate synthase (DHBPS)). It was intended to examine in vitro and in planta the enzymatic properties and the physiological importance of these three bipartite wild-type and multiple engineered RIBA variants, which were expressed in a lethal "riba" mutant. In addition, transgenic Arabidopsis plants with silenced and overexpressed RIBA1 genes were analyzed on the modified content of flavins and the flavor-coenzyme-dependent proteins and their cellular processes. A search for RIBA-interaction partners were aimed to decode the function, organization and control of riboflavin biosynthesis and the interrelation to other subcellular processes. In preliminary experiments RIBA1 phosphorylation was achieved with plastid extracts. In continuation we succeeded to identify multiple phosphorylation sites of RIBA1 and are currently continue to unravel the physiological consequences of RIBA phosphorylation in Arabidopsis riba1 mutant background. In addition, a novel gene encoding a bi-functional RIBF protein with FAD synthase/FAD hydrolase activity was identified and characterized in wild-type and mutant seedlings.
Projektbezogene Publikationen (Auswahl)
- (2016) Functional Analysis of RIBA, the Introductory Enzyme for Riboflavin Biosynthesis. Doctoral Thesis, Faculty of Life Sciences, Humboldt-Universität zu Berlin
Hiltunen H
- MapB Protein is the Essential Methionine Aminopeptidase in Mycobacterium tuberculosis. Cells. 2019 Apr 28;8(5)
Vanunu M, Schall P, Reingewertz TH, Chakraborti PK, Grimm B, Barkan D
(Siehe online unter https://doi.org/10.3390/cells8050393)
