Lipoteichoic acids (LTAs) have been shown to act as bacterial counterparts to the receptor binding proteins of LL-H, LL-H host range mutant LL-H-a21, and JCL1032. Here we have used LTAs purified by hydrophobic interaction chromatography from different phage-resistant and -sensitive strains of Lactobacillus delbrueckii subsp. lactis. Nuclear magnetic resonance analyses revealed variation in the degree of ␣-glucosyl and D-alanyl substitution of the 1,3-linked poly(glycerophosphate) LTAs between the phage-sensitive and phage-resistant strains. Inactivation of phages was less effective if there was a high level of D-alanine residues in the LTA backbones. Prior incubation of the LTAs with ␣-glucose-specific lectin inhibited the LL-H phage inactivation. The overall level of decoration or the specific spatial combination of ␣-glucosyl-substituted, D-alanyl-substituted, and nonsubstituted glycerol residues may also affect phage adsorption.Multiplication of phages requires the takeover of the host cell metabolism. The phage infection starts when phages adsorb irreversibly to the specific surface structures of the host bacterium. The rate of adsorption depends on external factors like medium, pH, temperature, and cofactors (e.g., cations) (2). Phage-host interactions during host recognition and attachment between enterobacteria phages , T5, and P22 and outer membrane receptors have been studied thoroughly (10,11,25,40,45). Less is known about phage receptors of gram-positive bacteria (16,37). Accessory polymers of the cell wall (such as polysaccharides and wall teichoic acids) (12,14,16), the peptidoglycan layer (44), and a few membrane proteins (22, 37) have been identified to serve as receptors for some Listeria, Bacillus subtilis, Staphylococcus aureus, Lactococcus lactis, and Lactobacillus phages.Bacteriophages cause economic losses by disrupting lactic acid bacteria during milk fermentation before the desired texture and flavor have been formed in the product. Lactobacillus delbrueckii subsp. lactis and Lactobacillus delbrueckii subsp. bulgaricus are used as starters in cheese and yogurt production. The double-stranded DNA genome of the virulent phage LL-H (34.6 kb) is so far the only L. delbrueckii phage genome to be completely sequenced (29). The LL-H gene product responsible for host recognition has been identified as Gp71 by utilizing the isolated LL-H-resistant mutant (Ads-5) of L. delbrueckii subsp. lactis ATCC 15808 and the LL-H host range mutants (35). The small isometric-headed phage LL-H, with a noncontractile tail, a baseplate, and a central tail fiber (5, 21), exhibits only limited DNA similarity to another L. delbrueckii phage, JCL1032 (20, 36). The C-terminal end of ORF474 of JCL1032 shows, however, high sequence similarity to Gp71 (35). We have previously shown that lipoteichoic acids (LTAs) interact specifically with certain L. delbrueckii phages (34). LTAs most probably act as bacterial counterparts to the receptor binding proteins of LL-H, LL-H-a21, and JCL1032, thus representing a new class of phag...

Lipoteichoic acids (LTAs) were purified from Lactobacillus delbrueckii subsp. lactis ATCC 15808 and its LL-H adsorption-resistant mutant, Ads-5, by hydrophobic interaction chromatography. L. delbrueckii phages (LL-H, the LL-H host range mutant, and JCL1032) were inactivated by these poly(glycerophosphate) type of LTAs in vitro in accordance to their adsorption to intact ATCC 15808 and Ads-5 cells.