Binding toxin

CM101 Analog of group B streptococcus toxin, binds to tumor endothelium, induces inflammation... 

Figure 8. A schematic for the toxin binding sites on the voltage-gated Na channel. Toxin-free open and closed conformations are drawn at the left and center. Separate sites are depicted within the membrane for activators such as BTX, VTD (A), and brevetoxin (B) these are coupled to each other and to the a-peptide toxin site (a), which is kinetically linked to the -peptide toxin site (P see ref. 20). Near the outer opening of the pore is a site (G) for STX and TTX which is affected by binding at site A and which can modify inactivation gating.

In addition to variations in toxin structure, the nature of the binding site and the medium in which binding occurs both influence the observed behavior of the toxins and can be systematically varied to study the toxin/binding site interaction. These factors will not be discussed at length here, but should be remembered as complications in comparing different data sets. 

With respect to toxins which target specific sites, insight can be obtained from the anomolies that are observed. For example, both puffer fish and tetrodotoxin-containing crabs (96) are insensitive to tetrodotoxin. The investigation of such insensitivities can provide information about membrane channels and their toxin binding sites. 

I. Vrasidas, J. Kemmink, R. M. J. Liskamp, and R. J. Pieters, Synthesis and Cholera Toxin binding properties of a lactose-2-aminothiazoline conjugate,... 

A. Yamada, K. Hatano, K. Matsuoka, T. Koyama, Y. Esumi, H. Koshino, K. Hino, K. Nishikawa, Y. Natori, and D. Terunuma, Syntheses and Vero toxin-binding activities of carbosilane, Tetrahedron, 62 (2006) 5074—5083. 

The antibody preparations could be administered unaltered or (more commonly) after their conjugation to radioisotopes or toxins. Binding of unaltered monoclonal antibodies to a tumour surface alone should facilitate increased destruction of tumour cells (Figure 13.4). This approach, however, has yielded disappointing results, as the monoclonal antibody preparations used to date have been murine in origin. The Fc region of such mouse antibodies is a very poor activator of human immune function. Technical advances, allowing the production of human/humanized monoclonals (see later) may render this therapeutic approach more attractive in the future. 

Stiles, B.G., Blocker, D., Hale, M.L., Guettholf, M.A. and Barth, H., Clostridium botulinum C2 toxin binding studies with fluorescence-activated cytometry, Toxicon, 40, 1135-1140, 2002. 

Each type of channel is a unique protein which, in principle, could be uniquely targeted for purposes of drug design. Q- and R-type channels have also been described on the basis of polypeptide toxin binding studies, but have not been extensively exploited for... 

Losytska V, Naida I, Tsiganov V (1997) Toxin-binding abihty of blood serum proteins in burned patients with the use of Enterosgel. In Biosorption methods and preparations in prophylactic and therapeutic practice, Eirst Conference, Kyiv (In Ukrainian), pp 121-122... 

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