Characterization, crystallization and preliminary X-ray diffraction analysis of acutohaemolysin, a haemolytic toxin from Agkistrodon acutus venom

Acutohaemolysin, a phospholipase A(2) (PLA(2)) from the venom of the snake Agkistrodon acutus, has been isolated and purified to homogeneity by anion- exchange chromatography on a DEAE-Sepharose column followed by cation-excha nge chromatography on a CM-Sepharose column. It is an alkaline protein with an isoelectric point of 10.5 and is comprised of a single polypeptide chai n of 13 938 Da. Its N-terminal amino-acid sequence shows very high similari ty to Lys49-type PLA(2) proteins from other snake venoms. Although its PLA( 2) enzymatic activity is very low, acutohaemolysin has a strong indirect ha emolytic activity and anticoagulant activity. Acutohaemolysin crystals with a diffraction limit of 1.60 Angstrom were obtained by the hanging-drop vap our-diffusion method. The crystals belong to the space group C2, with unit- cell parameters a = 45.30, b = 59.55, c = 46.13 Angstrom, beta = 117.69 deg rees. The asymmetric unit contains one molecule.