Of information transfer in biological systems and perform their duties by interacting with glycoproteins, glycolipids and oligosaccharides [1]. They are found in a wide range of organisms including viruses, bacteria, plants 
and animals, and are believed to play an important role in cell-cell interactions [2]. Bacteria possess several different types of lectins [3], including for example FimH which is located at the top of type 1 pili from the uropathogenic Escherichia coli and recognizes terminally located 1676428 D-mannose moieties on cell-bound LY2409021 glycoproteins mediating adhesion between the bacterium and the urothelium [4,5]. Furthermore, lectins may have a significant biotechnological and medical potential, as exemplified by the galactoside-specific mistletoe lectin, which is used on a large scale to support anti-cancer therapy [6]. P. aeruginosa, an opportunistic pathogen associated with chronic airway infections, synthesizes two lectins LecA and LecB (formerly named PA-IL and PA-IIL) [7]. Strains of P. aeruginosa that produces high levels of these virulence factors exhibit an increased virulence potential [8]. Both lectins play a prominent role in human infections, since it was demonstrated that P. aeruginosainduced otitis externa diffusa [9], as well as respiratory tract infections [10] including those in cystic fibrosis (CF) patients [11], could be successfully treated by application of a solution containing LecA and LecB- specific sugars. The sugar solutions presumably prevented the lectin-mediated bacterial adhesion to the corresponding host cells. The expression of lectin genes in P. aeruginosa is coordinately regulated with certain other virulence factors and controlled via quorum sensing and by the alternative sigma factor RpoS [12]. LecB consists of four 11.73 kDa subunits, each exhibiting a high binding constant for L-fucose (KD = 1.56106 M21) and its derivatives [13,14] and a somewhat lower binding constant for D-mannose (KD = 3.16102 M21). The crystal structure of LecB purified from E. coli showed a tetrameric organisation of the protein stabilized by Ca-ions with four sugar binding sites each composed of residues from two subunits [15,16,17]. Recently, we have demonstrated the N-glycosylation of LecB which appears to be required for proper transport to its final destination on the cell surface of P. aeruginosa [14]. In CF patients, increased terminal fucosylation of airway epithelial glycoproteins is found, as well as a higher percentage of sialylated and sulfated oligosaccharides in Lewis A oligosaccharide side chains, which presumably represent preferential ligands for LecB [16] thereby contributing significantly to chronic respiratory P. aeruginosa infections [18]. Interestingly, LecA and LecB also inhibit ciliary beating [19] which represents an important defence mechanism of the lung [20,21]. It was suggested that LecB is exposed on the surface of sessile P. aeruginosa cells, since the addition of L-fucose-branched chitosan led to specific cell aggregation [22]. In addition, it was shown that LecB is located in the bacterial outer membrane and a lecB-deficient P. aeruginosa strain is impaired in biofilm formation [23]. Addition ofLectin LecB Interacts with Porin OprFglycopeptide dendrimers targeting LecB resulted in complete inhibition and dispersion of biofilms, which clearly marks this lectin as a valuable target for developing P. aeruginosa biofilm inhibitors [24,25]. LecB is also Mirin web involved in the assembly of pili on the.Of information transfer in biological systems and perform their duties by interacting with glycoproteins, glycolipids and oligosaccharides [1]. They are found in a wide range of organisms including viruses, bacteria, plants and animals, and are believed to play an important role in cell-cell interactions [2]. Bacteria possess several different types of lectins [3], including for example FimH which is located at the top of type 1 pili from the uropathogenic Escherichia coli and recognizes terminally located 1676428 D-mannose moieties on cell-bound glycoproteins mediating adhesion between the bacterium and the urothelium [4,5]. Furthermore, lectins may have a significant biotechnological and medical potential, as exemplified by the galactoside-specific mistletoe lectin, which is used on a large scale to support anti-cancer therapy [6]. P. aeruginosa, an opportunistic pathogen associated with chronic airway infections, synthesizes two lectins LecA and LecB (formerly named PA-IL and PA-IIL) [7]. Strains of P. aeruginosa that produces high levels of these virulence factors exhibit an increased virulence potential [8]. Both lectins play a prominent role in human infections, since it was demonstrated that P. aeruginosainduced otitis externa diffusa [9], as well as respiratory tract infections [10] including those in cystic fibrosis (CF) patients [11], could be successfully treated by application of a solution containing LecA and LecB- specific sugars. The sugar solutions presumably prevented the lectin-mediated bacterial adhesion to the corresponding host cells. The expression of lectin genes in P. aeruginosa is coordinately regulated with certain other virulence factors and controlled via quorum sensing and by the alternative sigma factor RpoS [12]. LecB consists of four 11.73 kDa subunits, each exhibiting a high binding constant for L-fucose (KD = 1.56106 M21) and its derivatives [13,14] and a somewhat lower binding constant for D-mannose (KD = 3.16102 M21). The crystal structure of LecB purified from E. coli showed a tetrameric organisation of the protein stabilized by Ca-ions with four sugar binding sites each composed of residues from two subunits [15,16,17]. Recently, we have demonstrated the N-glycosylation of LecB which appears to be required for 
proper transport to its final destination on the cell surface of P. aeruginosa [14]. In CF patients, increased terminal fucosylation of airway epithelial glycoproteins is found, as well as a higher percentage of sialylated and sulfated oligosaccharides in Lewis A oligosaccharide side chains, which presumably represent preferential ligands for LecB [16] thereby contributing significantly to chronic respiratory P. aeruginosa infections [18]. Interestingly, LecA and LecB also inhibit ciliary beating [19] which represents an important defence mechanism of the lung [20,21]. It was suggested that LecB is exposed on the surface of sessile P. aeruginosa cells, since the addition of L-fucose-branched chitosan led to specific cell aggregation [22]. In addition, it was shown that LecB is located in the bacterial outer membrane and a lecB-deficient P. aeruginosa strain is impaired in biofilm formation [23]. Addition ofLectin LecB Interacts with Porin OprFglycopeptide dendrimers targeting LecB resulted in complete inhibition and dispersion of biofilms, which clearly marks this lectin as a valuable target for developing P. aeruginosa biofilm inhibitors [24,25]. LecB is also involved in the assembly of pili on the.
