2bvm: Difference between revisions

Toxin B is a member of the family of large clostridial cytotoxins which, are of great medical importance. Its catalytic fragment was crystallized, in the presence of UDP-glucose and Mn2+. The structure was determined at, 2.2 A resolution, showing that toxin B belongs to the glycosyltransferase, type A family. However, toxin B contains as many as 309 residues in, addition to the common chainfold, which most likely contribute to the, target specificity. A superposition with other glycosyltransferases shows, the expected positions of the acceptor oxygen atom during glucosyl, transfer and indicates further that the reaction proceeds probably along a, single-displacement pathway. The C1'' donor carbon atom position is, defined by the bound UDP and glucose. It assigns the surface area of toxin, B that forms the interface to the target protein during the modifying, reaction. A docking attempt brought the known acceptor atom, Thr37, O(gamma1) of the switch I region of the RhoA:GDP target structure, near, the expected position. The relative orientation of the two proteins was, consistent with both being attached to a membrane. Sequence comparisons, between toxin B variants revealed that the highest exchange rate occurs, around the active center at the putative docking interface, presumably due, to a continuous hit-and-evasion struggle between Clostridia and their, eukaryotic hosts.

2BVM is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Clostridium_difficile Clostridium difficile] with GLC, MN, SO4 and UDP as [http://en.wikipedia.org/wiki/ligands ligands]. Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2BVM OCA].  

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