1f8u: Difference between revisions

==Overview==

Structures of recombinant wild-type human acetylcholinesterase and of its, E202Q mutant as complexes with fasciculin-II, a 'three-finger' polypeptide, toxin purified from the venom of the eastern green mamba (Dendroaspis, angusticeps), are reported. The structure of the complex of the wild-type, enzyme was solved to 2.8 A resolution by molecular replacement starting, from the structure of the complex of Torpedo californica, acetylcholinesterase with fasciculin-II and verified by starting from a, similar complex with mouse acetylcholinesterase. The overall structure is, surprisingly similar to that of the T. californica enzyme with, fasciculin-II and, as expected, to that of the mouse acetylcholinesterase, complex. The structure of the E202Q mutant complex was refined starting, from the corresponding wild-type human acetylcholinesterase structure, using the 2.7 A resolution data set collected. Comparison of the two, structures shows that removal of the charged group from the protein core, and its substitution by a neutral isosteric moiety does not disrupt the, functional architecture of the active centre. One of the elements of this, architecture is thought to be a hydrogen-bond network including residues, Glu202, Glu450, Tyr133 and two bridging molecules of water, which is, conserved in other vertebrate acetylcholinesterases as well as in the, human enzyme. The present findings are consistent with the notion that the, main role of this network is the proper positioning of the Glu202, carboxylate relative to the catalytic triad, thus defining its functional, role in the interaction of acetylcholinesterase with substrates and, inhibitors.

==About this Structure==

[[Category: snake toxin]]