Expression, purification, and characterization of anuran saxiphilins using thermofluor, fluorescence polarization, and isothermal titration calorimetry.

Anuran saxiphilins (Sxphs) are "toxin sponge" proteins thought to prevent the lethal effects of small-molecule neurotoxins through sequestration. Here, we present a protocol for the expression, purification, and characterization of Sxphs. We describe steps for using thermofluor, fluorescence polarization, and isothermal titration calorimetry assays that probe Sxph:saxitoxin interactions using a range of sample quantities.

Definition of a saxitoxin (STX) binding code enables discovery and characterization of the anuran saxiphilin family.

American bullfrog () saxiphilin (Sxph) is a high-affinity "toxin sponge" protein thought to prevent intoxication by saxitoxin (STX), a lethal bis-guanidinium neurotoxin that causes paralytic shellfish poisoning (PSP) by blocking voltage-gated sodium channels (Nas). How specific Sxph interactions contribute to STX binding has not been defined and whether other organisms have similar proteins is unclear. Here, we use mutagenesis, ligand binding, and structural studies to define the energetic basis of Sxph:STX recognition.

Arsenite removal from drinking water by bark-based magnetic iron oxide particle (BMIOP): a column study.

The removal of arsenite [As(III)] from drinking water was investigated in a column at flow rates of 2.0 and 5.0 mL/min (up-flow direction) using bark-based magnetic iron oxide particles (BMIOP) prepared by coating (Fe(NO).

Discovery of a selective, state-independent inhibitor of Na1.7 by modification of guanidinium toxins.

The voltage-gated sodium channel isoform Na1.7 is highly expressed in dorsal root ganglion neurons and is obligatory for nociceptive signal transmission. Genetic gain-of-function and loss-of-function Na1.