NEW YORK, July 6 (GenomeWeb News) - Scientists at the Burnham Institute have determined the x-ray crystal structure of an anthrax toxin protein docked to a host cell receptor - a complex that governs the entry of the anthrax toxin into human cells.
The results of the study, published in the online version of the journal Nature on July 4, could provide new targets for anthrax antitoxins, as well as point the way toward engineered anthrax toxin molecules that would selectively attack tumor cells, the researchers said.
The study was funded by the National Institute of Allergy and Infectious Diseases and led by Robert Liddington of the Burnham Institute in
Anthrax toxin uses a protein known as protective antigen to bind to two different cell receptors: CMG2 and TEM8. The Burnham Institute team solved the 3D structure of the protective antigen protein/CMG2 complex. While previous studies had determined the 3D structures of the unbound anthrax protective antigen protein and the CMG2 receptor separately, the researchers said that the protein complex offers clearer targets for researchers working on anthrax antitoxins.
In addition, Liddington said that the structure could lead to a potential new tumor treatment using a genetically modified anthrax toxin based on the TEM8 cell receptor. Although the structure of the TEM8 receptor has not been determined, "Computer modeling could enable us to design a version of the anthrax toxin that binds only to TEM8 and not to CMG2," which would kill tumor cells while leaving ordinary cells intact, Liddington said.