Molecular Recognition in Biological Systems and Bioinformatics

Where is the active face of ProTx-II?

Protein structure and function; voltage-sensitive ion channels; proteomics; mass spectrometry.

Analysis of the effects of peptide toxins on gating kinetics in voltage-sensitive sodium channels has identified a potentially novel modulator of channel activation, the spider toxin ProTx-II. This polypeptide inhibits channel activation with high affinity, although it does not interact at any of the channel sites previously associated with gating. ProTx-II displays a high degree of isoform selectivity among sodium channels, and interacts most tightly with the form present in peripheral nerves, and is thought to be involved in sensing of chronic pain. Because we have found that ProTx-II binds directly to phospholipid vesicles (Smith et al, JBC, 2005, p. 11127), and have also demonstrated that most of the amino acid residues which contribute to its activity are hydrophobic (Smith et al, JBC, 2007, p. 12687), we suggest that its ability to modulate channel activity may involve immobilization of annular phospholipids which surround the channel molecule as well as direct interactions with the channel itself. If this model is correct, it could help to explain the unusual ability of ProTx-II to modify both Na and Ca channels with a high degree of isoform selectivity. Because the preferred molecular target of ProTx-II is the peripheral nerve sodium channel involved in chronic pain sensing, this toxin may provide a good template for the development of drugs designed to alleviate this condition.

The lab also supports a number of projects in functional proteomics. Two recent studies in which we have participated have identified a number of proteins whose expression is dysregulated in ear after treatment with cisplatin (Coling et al Hearing Res., 2007), or in hibernating heart (Page et al, Circ. Res. 2008).

• HPLC
• CD Spectropolarimeter

Insight/Discover via Koudelka site license

Human

• Anemone and spider toxins
• Voltage-gated sodium channels

Cardiac arrhythmia, drug design

• Whole cell voltage clamp
• Maldi-tof MS
• HPLC
• Spectropolarimetry
• The usual molecular biology suspects

• HEK-293
• tsa201

Cardiovascular

Heart, muscle, nerve

http://www.smbs.buffalo.edu/bch/faculty/blumenthal