Wang Z, Choice E, Kaspar A, Hanson D, Okada S, Lyu S C, Krensky A M, Clayberger C
Departments of Cardiothoracic Surgery and Pediatrics, Stanford University, Stanford, CA 94305, USA.
J Immunol. 2000 Aug 1;165(3):1486-90. doi: 10.4049/jimmunol.165.3.1486.
Granulysin, a 9-kDa protein localized to human CTL and NK cell granules, is cytolytic against tumor cells and microbes. Molecular modeling predicts that granulysin is composed of five alpha-helices separated by short loop regions. In this report, synthetic peptides corresponding to the linear granulysin sequence were characterized for lytic activity. Peptides corresponding to the central region of granulysin lyse bacteria, human cells, and synthetic liposomes, while peptides corresponding to the amino or carboxyl regions are not lytic. Peptides corresponding to either helix 2 or helix 3 lyse bacteria, while lysis of human cells and liposomes is dependent on the helix 3 sequence. Peptides in which positively charged arginine residues are substituted with neutral glutamine exhibit reduced lysis of all three targets. While reduction of recombinant 9-kDa granulysin increases lysis of Jurkat cells, reduction of cysteine-containing granulysin peptides decreases lysis of Jurkat cells. In contrast, lysis of bacteria by recombinant granulysin or by cysteine-containing granulysin peptides is unaffected by reducing conditions. Jurkat cells transfected with either CrmA or Bcl-2 are protected from lysis by recombinant granulysin or the peptides. Differential activity of granulysin peptides against tumor cells and bacteria may be exploited to develop specific antibiotics without toxicity for mammalian cells.
颗粒溶素是一种定位于人类细胞毒性T淋巴细胞（CTL）和自然杀伤（NK）细胞颗粒中的9千道尔顿蛋白质，对肿瘤细胞和微生物具有细胞溶解作用。分子模型预测颗粒溶素由五个α螺旋组成，中间由短环区域隔开。在本报告中，对与颗粒溶素线性序列相对应的合成肽进行了溶细胞活性表征。与颗粒溶素中央区域相对应的肽可裂解细菌、人类细胞和合成脂质体，而与氨基或羧基区域相对应的肽则无裂解作用。与螺旋2或螺旋3相对应的肽可裂解细菌，而对人类细胞和脂质体的裂解则取决于螺旋3序列。将带正电荷的精氨酸残基替换为中性谷氨酰胺的肽对所有三种靶标的裂解作用均降低。虽然重组9千道尔顿颗粒溶素的还原增加了对Jurkat细胞的裂解，但含半胱氨酸的颗粒溶素肽的还原却降低了对Jurkat细胞的裂解。相反，重组颗粒溶素或含半胱氨酸的颗粒溶素肽对细菌的裂解不受还原条件的影响。用CrmA或Bcl-2转染的Jurkat细胞可免受重组颗粒溶素或肽的裂解。颗粒溶素肽对肿瘤细胞和细菌的不同活性可用于开发对哺乳动物细胞无毒性的特异性抗生素。
