Insight into structure - function relationships of Ralstonia solanacearum lectins RSL, RS-IIL and RS20L
Nikola Kostlánová1, Edward P. Mitchell2, Nechama Gilboa-Garber3, Michaela Wimmerová1 and Anne Imberty4
1National Centre for Biomolecular Research and Department of Biochemistry, Masaryk University, Kotlářska 2, 61137 Brno, Czech Republic, 2E.S.R.F. Experiments Division, BP 220, F-38043, Grenoble Cedex, France, 3Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel, 4CERMAV-CNRS, BP 53, F-38041, Grenoble, Cedex 09, France
Lectins are a class of proteins of non-immune and non-enzymatic origin that bind carbohydrates specifically and reversibly. They express numerous biological activities, nearly all of which are based on their acting as recognition determinants in diverse biological processes including fertilization, pathogen-cell adhesion and recognition, inflammatory response and others. A number of pathogen microorganisms utilize lectin-carbohydrate interaction to recognized and infect host organism. The comprehension of the molecular mechanisms which gives a pathogenic bacterium the ability to invade, colonize and reorient the physiopathology of its host is a goal of primary importance and such studies may direct the conception of new strategies to fight these pathogenic agents.
Ralstonia solanacearum is soil-born bacterium, which belongs to the group of beta-proteobacteria. It is responsible for bacterial wilts on more than 200 plant species including potato, tomato banana and others economically important corps . R. solanacearum, which is capable of living for prolonged periods in the soil, infects its hosts beginning with the root system and presents a very strong tropism for the xylem vessels. Its extensive multiplication in the water-conducting system leads to a systemic infection of the plant.
This contribution describes three lectins RSL (9.9 kDa) , RS-IIL (11.6 kDa)  and RS20L (20 kDa) that have been found in R. solanacearum extract and purified using affinity chromatography. All lectins were crystallized by vapor diffusion and high and ultra-high (in case of 0.94Å resolution of RSL/a-methylfucoside) resolution data were collected at ESRF, Grenoble, France. The structural data have been supplemented by ITC microcalorimetry and surface plasmon resonance studies defining lectins specificity to carbohydrates including those, which are commonly present in nature and may be the target for the lectins in plants.
 Salanoubat, M., Genin, S., Artiguenave, F., Gouzy, J., Mangenot, S., Arlat, M., Billault, A., Brottier, P., Camus ,J.C., Cattolico, L., Chandler, M., Choisne, N., Claudel-Renard, C., Cunnac, S., Demange, N., Gaspin, C., Lavie, M., Moisan, A., Robert, C., Saurin, W., Schiex, T., Siguier, P., Thebault, P., Whalen, M., Wincker, P., Levy, M., Weissenbach, J. & Boucher, C.A., Nature,. 415 (2002) 497-502
 Kostlánová, N., Mitchell, E., Lortat-Jacob, H., Oscarson, S., Lahmann, M., Gilboa-Garber, N., Chambat, G., Wimmerová, M., & Imberty, A., J Biol Chem, in press
 Sudakevitz, D., Kostlánová, N., Blatman-Jan, G.,Mitchell, E., Lerrer, B., Wimmerová, M. Katcoff, D.J., Imberty, A. & Gilboa-Garber, N., Mol. Microbiol., 52(3) (2004), 691-700