Attachment of phosphorylcholine residues to pneumococcal teichoic acids and modification of substitution patterns by the phosphorylcholine esterase.

The bacterial lung pathogen has a unique nutritional requirement for exogenous choline and attaches phosphorylcholine (-Cho) residues to the GalNAc moieties of its teichoic acids (TAs) in its cell wall. Two phosphorylcholine transferases, LicD1 and LicD2, mediate the attachment of -Cho to the O-6 positions of the two GalNAc residues present in each repeating unit of pneumococcal TAs (pnTAs), of which only LicD1 has been determined to be essential. At the molecular level, the specificity of the -Cho attachment to pnTAs by LicD1 and LicD2 remains still elusive.

Proteomic response of Streptococcus pneumoniae to iron limitation.

Iron is an essential trace element and involved in various key metabolic pathways in bacterial lifestyle. Within the human host, iron is extremely limited. Hence, the ability of bacteria to acquire iron from the environment is critical for a successful infection.

Lipoteichoic acid deficiency permits normal growth but impairs virulence of Streptococcus pneumoniae.

Teichoic acid (TA), a crucial cell wall constituent of the pathobiont Streptococcus pneumoniae, is bound to peptidoglycan (wall teichoic acid, WTA) or to membrane glycolipids (lipoteichoic acid, LTA). Both TA polymers share a common precursor synthesis pathway, but differ in the final transfer of the TA chain to either peptidoglycan or a glycolipid. Here, we show that LTA exhibits a different linkage conformation compared to WTA, and identify TacL (previously known as RafX) as a putative lipoteichoic acid ligase required for LTA assembly.

Lipoteichoic acid of Streptococcus oralis Uo5: a novel biochemical structure comprising an unusual phosphorylcholine substitution pattern compared to Streptococcus pneumoniae.

Members of the Mitis group of streptococci possess teichoic acids (TAs) as integral components of their cell wall that are unique among Gram-positive bacteria. Both, lipoteichoic (LTA) and wall teichoic acid, are formed by the same biosynthetic pathway, are of high complexity and contain phosphorylcholine (P-Cho) residues. These residues serve as anchors for choline-binding proteins (CBPs), some of which have been identified as virulence factors of the human pathogen Streptococcus pneumoniae.