Phosphorylcholinemodified

Phosphorylcholinemodified refers to molecules that carry a covalently attached phosphorylcholine (PC) moiety. The PC group is a zwitterionic head derived from choline phosphate; its attachment to lipids, carbohydrates, or proteins alters surface charge, hydration, and interactions with host and microbial partners. The term is commonly used in microbiology and biochemistry to describe this modification on cell surfaces and secreted molecules.

In bacteria, PC modification is especially well documented on teichoic and lipoteichoic acids of Gram-positive organisms. Phosphocholine transferases, such as LicD family enzymes, transfer PC from donor molecules like CDP-choline to target polymers. The presence of PC on the bacterial surface can affect adhesion, resistance to cationic peptides, and immune recognition. Streptococcus pneumoniae is a classic example where PC decoration promotes binding to the platelet-activating factor receptor on host cells.

Biological implications include molecular mimicry of host phosphocholine epitopes, modulation of complement activation, and evasion of certain immune responses. PC modification can also influence interactions with choline-binding proteins and may contribute to tissue colonization and virulence in some pathogens.

PC modification is not limited to bacteria; certain eukaryotic parasites and surface proteins display phosphorylcholine epitopes, which can be targeted by anti-phosphocholine antibodies. These features have made PC-modified molecules subjects of interest for vaccines and serological assays.

Detection and study rely on mass spectrometry, immunoassays using anti-PC antibodies, and chromogenic or fluorescent labeling to map PC-bearing sites on macromolecules.