What is the active component of lipopolysaccharide (LPS)?

The active component of lipopolysaccharide (LPS) is Lipid A. LPS is a complex molecule found in the outer membrane of Gram-negative bacteria, and it plays a significant role in the structural integrity of the bacterial membrane as well as in the immune response of the host.

Lipid A is responsible for the endotoxin activity associated with LPS, which can trigger strong immune responses in host organisms. When bacteria die and this component is released, it can lead to severe inflammatory responses, including fever and septic shock. This makes Lipid A particularly important in understanding how Gram-negative infections can impact human health.

Regarding the other options: Peptidoglycan is a component of the bacterial cell wall but is not part of LPS. Protein A is associated with the cell wall of Staphylococcus aureus and is not related to LPS. Teichoic acid is primarily found in the cell walls of Gram-positive bacteria and does not have a role in the structure or function of LPS. Understanding these distinctions is essential for studying bacterial structures and their implications in infections.