摘要
钙离子是磷脂酶Ａ２催化必须的辅因子，以蝮蛇毒酸性磷脂酶Ａ２为材料，采用在晶体培养液中加入ＥＤＴＡ或ＥＧＴＡ螯合剂络合法除去ＰＬＡ２中可能有的Ｃａ２＋离子和加入ＣａＣｌ２以确保ＰＬＡ２能克分结合上钙离子的方法培养充分结合Ｃａ２＋和脱Ｃａ２＋的ＰＬＡ２晶体。加了螯合剂后长出的晶体为长棒状六方柱，加Ｃａ２＋离子后长出的晶体则为短粗的六方柱。经Ｘ射线鉴定两种晶体为同晶型，空间群为Ｐ６１，晶胞参数很接近。现已收集到这两种晶体的高分辨率衍射数据。进一步的结构分析和结构比较将有助于详细和清楚地分析Ｃａ２＋离子对分子构象的影响。
The Ca2+ ion is a cofactor for the catalysis of phospholipase A2.The crystals of Ca2+ -free or Ca2+ -binding acidic phospholipase A2 from the venom of Agkistrodon halys pallas was obtained by adding chelate agent EDTA or EGTA to rid of Ca2+ existing possibly in PLA2,or adding CaCl2 to make PLA2 bind Ca2+ completely.The Crystal grown in the presence of chelate compound appears as long hexagonal rod,which is similar to that in the absence of the chelate compounds.The crystal obtained in solution containing high concentration Ca2+ shows a shape of short and thick rod.Both crystals belong to same space group (P61)and have similar unit cell dimensions.The high resolution deffraction data were collected for these two kinds of crystals.The effects of Ca2+ ion on PLA2 conformation will be assessed by the further structure analysis and structure comparison.
出处
《生物物理学报》
CSCD
北大核心
1996年第2期183-186,共4页
Acta Biophysica Sinica
基金
国家自然科学基金
中国科学院重大项目
