| dc.description.abstract | Pathogenic bacteria employ an array of biological macromolecules and cellular
structures that help in the initiation and progression of disease in host organism.
These ‘virulence factors’ can either be secreted by the bacterium, or membrane-
associated, or a component of the cytosol. Virulence factors are critical for host
invasion, manifestation of the diseased condition and for evasion of host immune
response. Prominent examples of bacterial virulence factors are motility factors such
as flagella, adherence factors like pili, capsules that mask bacteria from phagocytosis,
siderophores to enable iron uptake, virulence plasmids, endotoxins such as the
lipopolysaccharides (LPS) in the cell wall of Gram-negative bacteria, exotoxins such
as neurotoxins, pore-forming toxins, and host invasion factors such as effector
proteins secreted by the membrane-bound secretion systems. For successful
colonization and concomitant pathogenesis, virulence factors must first breach the
protective barriers of the host – skin or the mucous membrane and gain entry within
tissues or the bloodstream. Bacterial pathogens thus adopt various strategies to enable
their uptake by modulating host membranes. The work presented in this thesis aims
to obtain structural insights into how certain classes of membrane-binding virulence-
associated proteins interact with host membrane lipids, with the help of single-particle
cryo-electron microscopy. Overall, our study shows that EspB is a membrane-binding effector protein of the
T7SS, which has affinity for anionic phospholipids such as PA, PS and PIPs, in host
cell membrane.
In summary, this thesis outlines the interaction of bacterial pore-forming toxin VCC
and T7SS secreted substrate EspB, with lipids of the host membrane. Structural
information on how virulence-associated proteins bind to the host membrane and
their lipid specificity can help develop alternative therapeutic measures to combat
resistance of pathogenic bacteria to existing treatment regimens | en_US |
