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Analysis Biomolecular Interactions of Full-length NADase and SLO by BLI (CAT#: STEM-MB-0177-CJ)

Introduction

SLO, a cholesterol-dependent cytolysin (CDC), acts, at least in part, by disruption of eukaryotic cell membranes. Like other CDCs, it oligomerizes on the surface of cells and inserts into the membrane to create a large pore. Sufficient damage to the cell membrane results in cell death, as demonstrated in studies using macrophages, neutrophils, keratinocytes, and red blood cells. At sublytic concentrations, SLO has been shown to inhibit degranulation of neutrophils. SLO thus contributes to bacterial evasion of phagocytosis and resistance to killing by the immune system.<br /><br />NADase can cleave NAD to produce nicotinamide and adenosine diphosphoribose in mammalian cells, thereby promoting cytotoxicity through depletion of energy stores. Its subunit architecture includes an N-terminal translocation domain and a C-terminal catalytic domain that harbors NADase activity. <br /><br />SLO and NADase are known to be intimately associated with one another during infection. It is thought that SLO mediates translocation of NADase across the cell membrane in a mechanism that is independent of pore formation. The pathogen is better able to survive after internalization into keratinocytes in the presence of both SLO and NADase through inhibition of maturation of autophagosomes that contain intracellular GAS.




Principle

Bio-Layer Interferometry (BLI) is an optical technique for measuring macromolecular interactions by analyzing interference patterns of white light reflected from the surface of a biosensor tip. BLI experiments are used to determine the kinetics and affinity of molecular interactions. In a BLI experiment, one molecule is immobilized to a Dip and Read Biosensor and binding to a second molecule is measured. A change in the number of molecules bound to the end of the biosensor tip causes a shift in the interference pattern that is measured in real-time.

Applications

Toxicology

Procedure

1. Detect Buffers and prepare samples. BLI experiments are set up with one molecule immobilised on the surface of the biosensor (load sample) and a second molecule in solution (the analytical sample).
2. Fix the load sample on the biocompatible biosensor while the analytical sample is in solution.
3. The biosensor tip is immersed in the solution so that the target molecule begins to bind to the analysis sample.
4. Set up and run the BLI experiment. Molecules bound to or dissociated from the biosensor can generate response curves on the BLI system; unbound molecules, changes in the refractive index of the surrounding medium or changes in flow rate do not affect the interferogram pattern.
5. Collect and analyse data on the BLI's system.

Materials

• Equipment: Gator® Bio-Layer Interferometry (BLI)
• Sample Type: DNA, RNA, Protein, Antibodies, Peptides, Small Molecules