1FSC

Crystal Structure of Fasciculin 2 from Green Mamba Snake Venom: Evidence for Unusual Loop Flexibility

Summary for 1FSC

• Entry DOI: 10.2210/pdb1fsc/pdb
• Descriptor: FASCICULIN 2, UNKNOWN LIGAND (3 entities in total)
• Functional Keywords: snake toxin
• Biological source: Dendroaspis angusticeps (eastern green mamba)
• Total number of polymer chains: 1
• Total formula weight: 6768.77

Authors

Housset, D.,Le Du, M.H.,Fontecilla-Camps, J.C. (deposition date: 1995-03-27, release date: 1995-07-10, Last modification date: 2024-10-16)

Primary citation

le Du, M.H.,Housset, D.,Marchot, P.,Bougis, P.E.,Navaza, J.,Fontecilla-Camps, J.C.
Structure of fasciculin 2 from green mamba snake venom: evidence for unusual loop flexibility.
Acta Crystallogr.,Sect.D, 52:87-92, 1996

PubMed Abstract: 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.

PubMed: 15299729
DOI: 10.1107/S0907444995007517

Experimental method

X-RAY DIFFRACTION (2 Å)