Chang Y F, Young R, Post D, Struck D K
Department of Biochemistry and Biophysics, College of Agriculture, Texas A&M University, College Station 77843.
Infect Immun. 1987 Oct;55(10):2348-54. doi: 10.1128/iai.55.10.2348-2354.1987.
The identification and chromatographic characterization of the leukotoxin of Pasteurella haemolytica is described. The toxin, which has an apparent native molecular weight of greater than 400,000 as judged by gel exclusion chromatography, has a 105-kilodalton (105K) polypeptide as its major protein component. The proteolytic degradation of the 105K polypeptide could be correlated with the loss of toxin activity in aging cultures of P. haemolytica. Antisera raised against purified 105K polypeptide neutralized toxin activity. A 3.9-kilobase-pair fragment of the P. haemolytica genome cloned into a plasmid vector resulted in the production of intracellular toxin in Escherichia coli host cells. The restriction map of this clone shows significant overlap with the map of a previously reported leukotoxin clone (R. Y. C. Lo, P. E. Shewen, C. A. Strathdee, and C. N. Greer, Infect. Immun. 50:667-671, 1985). Finally, antisera raised against the 105K species labeled the P. haemolytica cell surface in a nonuniform, punctate manner.
本文描述了溶血巴斯德氏菌白细胞毒素的鉴定及色谱特征。通过凝胶排阻色谱法判断，该毒素的天然表观分子量大于400,000，其主要蛋白质成分是一种105千道尔顿（105K）的多肽。105K多肽的蛋白水解降解与溶血巴斯德氏菌老化培养物中毒素活性的丧失相关。针对纯化的105K多肽产生的抗血清可中和毒素活性。将溶血巴斯德氏菌基因组的一个3.9千碱基对片段克隆到质粒载体中，可在大肠杆菌宿主细胞中产生细胞内毒素。该克隆的限制性图谱与先前报道的白细胞毒素克隆图谱（R.Y.C. Lo、P.E. Shewen、C.A. Strathdee和C.N. Greer，《感染与免疫》50:667 - 671, 1985）显示出显著重叠。最后，针对105K蛋白产生的抗血清以不均匀的点状方式标记溶血巴斯德氏菌细胞表面。
