How lactobacilli synthesize inulin: characterization of ructosyltransferase enzymes
PhD ceremony: Mr. M.A. Anwar, 16.15 uur, Academiegebouw, Broerstraat 5, Groningen
Thesis: How lactobacilli synthesize inulin: characterization of ructosyltransferase enzymes
Promotor(s): prof. L. Dijkhuizen
Faculty: Mathematics and Natural Sciences
Lactic acid bacteria are common in our everyday foods and they make an important contribution to healthy bacterial microflora of mucous membranes and gastrointestinal tract (probiotics). In the work presented by Munir Anwar, he characterized three inulosucrase (and one levansucrase) enzymes from human associated lactobacilli. Only three inulosucrase enzymes had been characterized before the work reported in his thesis was initiated. His studies provided the first time evidence that cells ofLactobacillus johnsonii NCC 533 and Lactobacillus gasseri DSM 20604 convert sucrose in inulin and inulin fructooligosaccharides (FOS) in situ, highlighting their probiotic potential. The study of Anwar also indicated the occurrence of frequent genetic modifications in the ecological niches of these lactobacilli.
The inulosucrase protein sequences that had become available were used in alignments to identify amino acids that are well conserved in inulosucrases but not in levansucrases. These residues were targets for site-directed mutagenesis studies aiming to determine their functional roles. The results of these mutagenesis studies provided a better fundamental understanding of differences between inulosucrase/levansucrase enzymes, and are important for the construction of inulosucrase mutants with higher transglycosylation specificity, higher catalytic rates, and different FOS/polymer size distribution. Finally, these studies resulted in elucidation of the first 3D structure of an inulosucrase protein (InuJ) of Lb. johnsonii NCC 533 (in collaboration with Tjaard Pijning and Bauke Dijkstra, Biophysical Chemistry). Based on this 3D structure, future work may succeed in elucidating the structural basis for the observed differences in product specificity (β(2-1) or β(2-6) linkages) of inulosucrase and levansucrase enzymes.
Last modified: | 13 March 2020 01.13 a.m. |
More news
-
15 April 2025
1.5 million funding from Province of Groningen for innovative technology in the region
The University of Groningen will receive nearly 1.5 million euros in funding from the Province of Groningen to assist entrepreneurial academic researchers in developing innovative ideas into a startup.
-
15 April 2025
Nathalie Katsonis wins Ammodo Science Award 2025
For her pioneering research on molecular systems, Nathalie Katsonis receives the Ammodo Science Award for fundamental research 2025.
-
15 April 2025
Fundamental research with life-size effects
Nathalie Katsonis has won the Ammodo Science Award for Fundamental Research. She develops adaptive molecular materials and studies the chemical origins of life, which in turn yield insights for vaccines and clearing up oil spills at sea.