Lactobacillus buchneri Cell Wall Glycobiology
Description: Lactobacillus buchneri CD034 is a Gram-positive lactic acid bacterium (LAB) with GRAS (generally regarded as safe) status that was isolated from silage samples. Due to its possible utilization in food sciences L. buchneri is an ideal candidate organism for cell surface display of biofunctional compounds. Prior to establishment of such a system it is required to completely characterize both the cell surface and cell wall architeture of this organism at the biochemical and molecular level. Preliminary investigations have shown that L. buchneri CD034 is completely covered by a 2D crystalline cell surface (S-)layer. The S-layer protein monomers are obviously modified by covalently attached carbohydrate chains. Previous analyses of a related organism, where both the S-layer glycan structure and a decapeptide O-glycosylation sequence have been identified, support such an assumption. This decapeptide O-glycosylation sequence was also found in a recent protein sequence analysis of the L. buchneri CD034 S-layer protein. The current project proposal is based on the knowledge of a recently performed whole genome sequence analysis of this organism (CD Laboratory for Genetically Modified Lactic Acid Bacteria; Prof. Reingard Grabherr) and the availability of molecular tool for genetic modification of L. buchneri CD034. There are three main topics of the project which have not been analyzed in any LAB so far. (i) The complete structural characterization of the S-layer glycans of L. buchneri CD034 and the functional analysis of key enzymes of the S-layer glycosylation pathway, based on a preliminary annotation of carbohydrate-active enzymes,. (ii) Biochemical and molecular analysis of the anchor molecule between S-layer and cell wall of L. buchneri CD034 . In this context novel, poorly investigated neutral oligosaccharides will be considered in addition to classical secondary cell wall polymers such as teichoic and lipoteichoic acids. (iii) If exopolysaccharides (EPS) are present, the biochemical and molecular characterization of these should be performed on this S-layer carrying organism. When L. buchneri CD034 is used as a cell surface display system, depending on the possible presence of the EPS on the cell wall, it might be necessary to shut-down EPS biosynthesis. In conclusion, with this GRAS organism the application potential of biofunctional S-layer glycoproteins should be considerably extended.
Funder: Austrian Science Fund
Amount: €297,600
Funding type: grant
Funder scheme: Principal Investigator Projects
Start date: 2012-02-01
End date: 2016-12-31
Investigator: Paul Messner (lead)
Institutions: BOKU University, Universität für Bodenkultur Wien
Subfield: Food Science
Domain: Life Sciences
Funded outputs count: 9
Funder award ID: P24305
OpenAlex ID: G453333757