Novel human secreted phospholipase A2 with homology to the group III bee venom enzyme
Novel human secreted phospholipase A2 with homology to the group III bee venom enzyme
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DOI：
10.1074/jbc.275.11.7492
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发表时间：
2000-03-17
影响因子：
4.8
通讯作者：
Lambeau, G
中科院分区：
文献类型：
--
作者：
Valentin, E;Ghomashchi, F;Lambeau, G
蛇毒和哺乳动物分泌型磷脂酶A（sPLA（2）s）与许多生理、病理和毒性过程有关。到目前为止，在脊椎动物如哺乳动物和蛇中已经发现了结构相关的I和II组sPLA（2），而In：sPLA（2）组主要在无脊椎动物如蜜蜂和蝎子的毒液中发现。全长cDNA编码19个残基的信号肽，随后是490个氨基酸的蛋白质，该蛋白质由中心sPLA（2）结构域（141个残基）和两侧的大的N-和C-末端区域（分别为130和219个残基）组成。sPLA（2）结构域与蜂毒sPLA（2）具有31%的同一性，并显示出包括10个半胱氨酸的III组sPLA（2）的所有特征。hGIII sPLA（2）基因由至少7个外显子组成，定位于染色体22 q。通过北方印迹分析，在肾脏、心脏、肝脏和骨骼肌中发现了4.4-脱氢酶hGIII转录物。hGIII sPLA（2）cDNA转染COS细胞后，sPLA（2）活性在培养基中积累，表明cDNA编码分泌酶。使用小的单层囊泡作为底物，发现hGIII sPLA（2）是一种钙依赖性酶，对磷脂酰甘油的偏好是磷脂酰胆碱的11倍，在pH 8时活性最佳。
Venom and mammalian secreted phospholipases A, (sPLA(2)s) have been associated with numerous physiological, pathological, and toxic processes. So far, structurally related group I and II sPLA(2)s have been found in vertebrates such as mammals and snakes, whereas group In: sPLA(2)s have mainly been found in venom from invertebrates such as bees and scorpions Here we report the cloning and expression of a cDNA coding for a human group III (hGIII) sPLA(2). The full-length cDNA codes for a signal peptide of 19 residues followed by a protein of 490 amino acids made up of a central sPLA(2), domain (141 residues) flanked by large N- and C-terminal regions (130 and 219 residues, respectively). The sPLA(2) domain is 31% identical to bee venom sPLA(2) and displays all of the features of group III sPLA(2)s including 10 cysteines. The hGIII sPLA(2) gene consists of at least 7 exons and maps to chromosome 22q. By Northern blot analysis, a 4.4-kilobase hGIII transcript was found in kidney, heart, liver, and skeletal muscle. Transfection of hGIII sPLA(2) cDNA in COS cells led to accumulation of sPLA(2) activity in the culture medium, indicating that the cDNA codes for a secreted enzyme, Using small unilamellar vesicles as substrate, hGIII sPLA(2) was found to be a Ca2+-dependent enzyme showing an 11-fold preference for phosphatidylglycerol over phosphatidylcholine and optimal activity at pH 8.