title: Purification, Crystal Growth and Preliminary X-ray Analysis of a Phospholipase A(2) from Venom of Agkistrondon acutus.
abstract: An acidic phospholipase A(2) from Agkistrondon acutus venom has been purified to homogeneity via four steps using CM-Sepharose, two times DEAE-Sepharose, and Mono Q FPLC. The molecular weight of the protein was about 16.5 kD and the isoelectric point was 4.3. The purified enzyme showed a potent inhibitory effect on platelet aggregation induced by ADP in human platelet-enriched plasma. The enzyme was then crystallized by hanging drop diffusion method using 2-methyl-2, 4-pentanediol as a precipitant. Two kinds of single crystals suitable for X-ray crystallographic studies were obtained. X-ray crystallographic analysis showed that both crystal forms belong to monoclinic system and space group P2(1). The cell dimensions of form I crystals were a = 43.48 Aring;, b = 71.49 Aring;, c = 43.85 Aring; and beta = 116.32 deg; Those of form II crystals were a = 49.25 Aring;, b = 38.33 Aring;, c = 70.25 Aring; and beta = 99.20 deg;. Complete diffraction data sets have been collected to medium resolution for the two crystal forms.
authors.affiliation: National Laboratory of Biomacromolecules, Institute of Biophysics, Academia Sinica, Beijing 100101, China. Lin@sun5.ibp.ac.cn
authors.forename: Hai-Long
authors.initials: HL
authors.lastname: Zhang
authors.forename: Zheng-Jiong
authors.initials: ZJ
authors.lastname: Lin
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Du
authors.forename: Yuan-Cong
authors.initials: YC
authors.lastname: Zhou