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1.9 ANGSTROM RESOLUTION STRUCTURE OF FASCICULIN 1, AN ANTI-ACETYLCHOLINESTERASE TOXIN FROM GREEN MAMBA SNAKE VENOM
Structural highlights
Function3SE1_DENAN Interferes with neuromuscular transmission by inhibiting the enzyme acetylcholinesterase (AChE) present at the neuromuscular junction. It selectively binds and inhibits with a 1:1 stoichiometry the mammalian and electric fish AChE at picomolar concentrations. It is highly specific for the peripheral site of AChE and blocks the entry of acetylcholine into the active site of the enzyme, thereby preventing its breakdown. It has been called fasciculin since after injection into mice it causes severe, generalized and long-lasting (5-7 hours) fasciculations.[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe crystal structure of fasciculin 1, a potent acetylcholinesterase inhibitor from green mamba snake venom, has been solved by the multiple isomorphous replacement method complemented with anomalous scattering and subsequently refined at 1.9-A resolution. The overall structure of fasciculin is similar to those of the short alpha-neurotoxins and cardiotoxins, with a dense core rich in disulfide bridges and three long loops disposed as the central fingers of a hand. A comparison of these three prototypic toxin types shows that fasciculin 1 has structural features that are intermediate between those of the other two molecules. Its core region, which can be defined as a continuous stretch of conserved residues, is very similar to that of erabutoxin b, whereas the orientation of its long loops resembles that of cardiotoxin VII4. This result introduces a new element in the study of phylogenetic relationships of snake toxins and suggests that, after divergency from an ancestral gene, convergent evolution may have played an important factor in the evolution of these proteins. In fasciculin 1, several arginine and lysine residues are well ordered and relatively exposed to the solvent medium and may play a role in the binding to the peripheral site of acetylcholinesterases. 1.9-A resolution structure of fasciculin 1, an anti-acetylcholinesterase toxin from green mamba snake venom.,le Du MH, Marchot P, Bougis PE, Fontecilla-Camps JC J Biol Chem. 1992 Nov 5;267(31):22122-30. PMID:1429564[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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