Tang, LiangZhou, Yuan-CongLin, Zheng-jiong2015-05-052015-05-051999-12-01Tang, L., Zhou, Y., & Lin, Z. (1999). Structure of agkistrodotoxin in an orthorhombic crystal form with six molecules per asymmetric unit. Acta Crystallographica Section D Biological Crystallography, 55(12), 1986-1996. http://www.dx.doi.org/10.1107/S0907444999012603https://hdl.handle.net/1808/17593This is the publisher's version, also available electronically from "http://scripts.iucr.org".The structure of agkistrodotoxin crystallized under basic conditions has been determined at 2.8 Å resolution by the molecular-replacement technique and refined to a crystallographic R factor of 0.194 and a free R factor of 0.260 with good stereochemistry. The molecular packing in the crystal differs from other PLA2s. The six molecules in the asymmetric unit form three dimers linked by Ca2+ ions in a near-perfect six-ligand octahedral coordinating system. Extensive intermolecular hydrophobic interactions occur at the interfacial recognition site of each neurotoxin molecule, which provides an insight into phospholipase A2-membrane interactions. This hydrophobic interaction-induced molecular association along the interfacial recognition site suggests a self-protection mechanism of agkistrodotoxin.agkistrodotoxinMolecular replacementCalcium ionshydrophobic interactionNeurotoxic sitephospholipase A2presynaptic neurotoxinArticle10.1107/S0907444999012603openAccess