Crystallization and preliminary X-ray diffraction analysis of a novel Arg49 phospholipase A₂ homologue from Zhaoermia mangshanensis venom

Zhaoermiatoxin, an Arg49 phospholipase A₂ homologue from Zhaoermia mangshanensis (formerly Trimeresurus mangshanensis, Ermia mangshanensis) venom is a novel member of the PLA₂-homologue family that possesses an arginine residue at position 49, probably arising from a secondary Lys49→Arg substitution that does not alter the catalytic inactivity towards phospholipids. Like other Lys49 PLA₂ homologues, zhaoermiatoxin induces oedema and strong myonecrosis without detectable PLA₂ catalytic activity. A single crystal with maximum dimensions of 0.2 × 0.2 × 0.5 mm was used for X-ray diffraction data collection to a resolution of 2.05 Å using synchrotron radiation and the diffraction pattern was indexed in the hexagonal space group P6₄, with unit-cell parameters a = 72.9, b = 72.9, c = 93.9 Å.