Levansucrases (EC 2.4.1.10) are bacterial extracellular enzymes which are splitting sucrose and polymerizing fructose residues. As reaction products, highly polymerized levan and fructo-oligosaccharides are produced. Both product types have application, for example as prebiotics or immune stimulators. Levansucrases of Gram-positive bacteria (Bacillus subtilis, B. megaterium) are well studied using protein crystallization and mutation. Data on levansucrases of Gram-negative bacteria are much less abundant, and only one levansucrase of these bacteria (LsdA of Gluconacetobacter diazotrophicus) has been crystallized. We have started biochemical and structure-function characterization of levansucrases of a Gram-negative plant-associated bacterium Pseudomonas syringae pv. tomato [1, 2, 3]. Here we will perform conservation analysis and modelling of the levansucrase (Lsc3) protein of Pseudomonas syringae pv. tomato DC3000 encoded by genomic locus PSPTOA0032. These data will be used for the selection of positions to be mutated for structure-function analysis, but also for interpretation of the properties of random mutants. The ConSurf server (http://consurf.tau.ac.il/) was used for in silico conservation analysis by submitting (i) the 3D model of Lsc3 predicted by ModBase on the basis of crystal structure of the ArFFase protein of Arthrobacter sp. K-1 (PDB: 3vss) and (ii) MUSCLE-alignment of 25 levansucrase protein sequences belonging to different bacteria and archaea. The output data of ConSurf analysis of the Lsc3 protein will be presented and discussed in the presentation.
Acknowledgements
This study was supported by grant GLOMR9072 from Estonian Science Foundation.
References
[1] Visnapuu, T. et al, 2009, Rapid Commun Mass Spectrom 23, 1337-46
[2] Visnapuu, T. et al, 2011, J Biotechnol 155, 338-49
[3] Alamäe T. et al, 2012, Carbohydr Chem, Vol 38. RSC, Cambridge, UK, 176-91
