Molecular Recognition in Biological Systems and Bioinformatics

Molecular Biology (general); heterologous protein expression and purification; two-electrode voltage clamp electrophysiology.

Synthesis, structure, and mechanism of association of a spider toxin for Kv4 channels

Many venomous organisms produce toxins that inhibit potassium channels. These compounds are valuable probes for understanding channel structure, and offer approaches to rational design of drugs directed at specific potassium channels. We have synthesized a spider toxin called HpTx2 in E. coli, and found that it is active against specific isoforms of Kv4 channels, but not Kv1.4 potassium channels. Future studies will focus on locating and characterizing the toxin's binding site on Kv4 channels, and understanding the details of its molecular interactions. Because of its unique specificity for an important heart channel, and its unusual mechanism of binding, a compound with properties similar to the toxin would have great promise as a drug for treatment of arrhythmias.

Ancillary subunits of the Kv4 potassium channels

We have recently cloned a group of calcium binding proteins that have been called KChIPs (K⁺ channel interaction proteins), which have been shown to be subunits of Kv4 potassium channels. We have identified a form which co-localizes with Kv4 channels in the heart, and shown that this his isoform interacts with the pore of the Kv4 channel. Future work will explore the mechanisms by which these proteins interact with, and modulation Kv4 channel function.

Ferret and Xenopus (oocytes)

• Voltage-gated K⁺ channels and their ancillary proteins
• Inhibitor cysteine knot spider toxins

• Cardiac arrhythmia
• Drug design

• Common Molecular Biology methods
• Protein chemistry
• Heterologous expression in E Coli
• Two electrode voltage clamp

http://www.acsu.buffalo.edu/~moralesm/