Etude du métabolisme du mannitol chez l'algue brune modèle Ectocarpus siliculosus : caractérisation de l'enzyme clé mannitol-1-phosphate déshydrogénase.

Abstract : Brown algae are multicellular photosynthetic organisms belonging to the stramenopile lineage and which are mainly found in the intertidal zone. One of their metabolic characteristics is to store carbon fixed by photosynthesis through the production of mannitol, a 6-carbon non-cyclic polyol. Synthesis and recycling of mannitol in these organisms occur through the mannitol cycle, which includes two steps for synthesis and two for recycling. Among brown algae, Ectocarpus siliculosus represents the model organisms to study different aspects of their biology. During the PhD thesis, three genes coding for the enzymes involved in the first step of the mannitol cycle, the mannitol-1-phosphate dehydrogenase (M1PDH), were studied (EsM1PDH1, EsM1PDH2, and EsM1PDH3). M1PDHs catalyze a reversible reaction between fructose-6-phosphate and mannitol-1-phosphate. One modified version of the EsM1PDH1 gene, coding for a N-terminal truncated protein in order to deleted a domain of unknown function, was overexpressed in the bacteria Escherichia coli. The truncated recombinant protein was purified and biochemically characterized, notably to determine kinetic parameters in both directions of the reversible reaction catalyzed by M1PDH. These results were completed by analysis of changes in expression of genes encoding enzymes involved in the mannitol cycle during the diurnal cycle. These observations contribute to increasing the understanding of a key metabolic pathway in brown algal physiology.
Document type :
Theses
Complete list of metadatas

Cited literature [137 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-01147231
Contributor : Abes Star <>
Submitted on : Thursday, April 30, 2015 - 9:17:05 AM
Last modification on : Friday, May 24, 2019 - 4:59:49 PM
Long-term archiving on: Monday, September 14, 2015 - 3:56:33 PM

File

2014PA066618.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-01147231, version 1

Citation

Patricia Bonin. Etude du métabolisme du mannitol chez l'algue brune modèle Ectocarpus siliculosus : caractérisation de l'enzyme clé mannitol-1-phosphate déshydrogénase.. Biochimie, Biologie Moléculaire. Université Pierre et Marie Curie - Paris VI, 2014. Français. ⟨NNT : 2014PA066618⟩. ⟨tel-01147231⟩

Share

Metrics

Record views

793

Files downloads

3639