1fsc
From Proteopedia
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CRYSTAL STRUCTURE OF FASCICULIN 2 FROM GREEN MAMBA SNAKE VENOM: EVIDENCE FOR UNUSUAL LOOP FLEXIBILITY
Overview
The crystal structure of the snake toxin fasciculin 2, a potent, acetylcholinesterase inhibitor from the venom of the green mamba, (Dendroaspis angusticeps), has been determined by the, molecular-replacement method, using the fasciculin 1 model and refined to, 2.0 A resolution. The introduction of an overall anisotropic temperature, factor improved significantly the quality of the electron-density map. It, suggests, as it was also indicated by the packing, that the thermal motion, along the unique axis direction is less pronounced than on the (ab) plane., The final crystallographic R factor is 0.188 for a model having r.m.s., deviations from ideality of 0.016 A for bond lengths and 2.01 degrees for, bond angles. As fasciculin 1, fasciculin 2 belongs to the three-finger, class of Elapidae toxins, a structural group that also contains the, alpha-neurotoxins and the cardiotoxins. Although the two fasciculins have, overall, closely related structures, the conformation of loop I differs, appreciably in the two molecules. The presence of detergent in, crystallization medium in the case of fasciculin 2 appears to be, responsible for the displacement of the loop containing Thr9. This, conformational change also results in the formation of a crystallographic, dimer that displays extensive intermolecular interactions.
About this Structure
1FSC is a Single protein structure of sequence from Dendroaspis angusticeps with O as ligand. Full crystallographic information is available from OCA.
Reference
Structure of fasciculin 2 from green mamba snake venom: evidence for unusual loop flexibility., le Du MH, Housset D, Marchot P, Bougis PE, Navaza J, Fontecilla-Camps JC, Acta Crystallogr D Biol Crystallogr. 1996 Jan 1;52(Pt 1):87-92. PMID:15299729
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