Cheng X, Nicolet J, Miserez R, Kuhnert P, Krampe M, Pilloud T, Abdo E M, Griot C, Frey J
Institute for Veterinary Bacteriology, University of Berne, Switzerland.
Microbiology (Reading). 1996 Dec;142 ( Pt 12):3515-24. doi: 10.1099/13500872-142-12-3515.
With the aim of characterizing specific immunogenic proteins of Mycoplasma mycoides subsp. mycoides small colony (SC) type, the aetiological agent of contagious bovine pleuropneumonia, a gene encoding a major immunogenic protein of 72 kDa named P72 was cloned and expressed in Escherichia coli. The expressed protein was of the same apparent molecular mass as that produced by the parent strain. The predicted molecular mass of P72, based on the DNA-deduced amino acid sequence, was 61.118 kDa, significantly lower than the apparent molecular mass of endogenous or recombinant P72 on SDS-PAGE. Analysis of the amino acid sequence revealed a typical prokaryotic signal peptidase II-membrane lipoprotein lipid attachment site and a transmembrane structure domain in the leader sequence at the amino-terminal end of the protein. P72 was shown to be a lipoprotein and its surface location was confirmed by trypsin treatment of whole cells. An unassigned gene encoding a peptide with some similarity to P72 was found on the genome sequence of M. capricolum subsp. capricolum but not on that of Mycoplasma genitalium. The P72 gene was detected in 11/11 M. mycoides subsp. mycoides SC strains. Antiserum against recombinant P72 reacted strongly with 12/12 strains of M. mycoides subsp. mycoides SC, weakly with Mycoplasma bovine group 7 strain PG50, but not with other members of the 'mycoides cluster' or closely related mycoplasmas. Cows experimentally contact-infected with M. mycoides subsp. mycoides SC developed a humoral response against P72 within 35 d. P72 is a specific antigenic membrane lipoprotein of M. mycoides subsp. mycoides SC with potential for use in development of diagnostic reagents. It seems to belong to a family of lipoproteins of the "mycoides cluster'.
为了鉴定丝状支原体丝状亚种小菌落（SC）型（牛传染性胸膜肺炎的病原体）的特定免疫原性蛋白，编码一种名为P72的72 kDa主要免疫原性蛋白的基因被克隆并在大肠杆菌中表达。表达的蛋白与亲本菌株产生的蛋白具有相同的表观分子量。根据DNA推导的氨基酸序列预测，P72的分子量为61.118 kDa，明显低于SDS-PAGE上内源性或重组P72的表观分子量。氨基酸序列分析显示，该蛋白氨基末端的前导序列中有一个典型的原核信号肽酶II-膜脂蛋白脂质附着位点和一个跨膜结构域。P72被证明是一种脂蛋白，通过对全细胞进行胰蛋白酶处理证实了其表面定位。在山羊支原体山羊亚种的基因组序列上发现了一个未分类的基因，其编码的肽与P72有一定相似性，但在生殖支原体的基因组序列上未发现。在11株丝状支原体丝状亚种SC菌株中均检测到P72基因。抗重组P72的抗血清与12株丝状支原体丝状亚种SC菌株强烈反应，与牛支原体7群PG50菌株反应较弱，但与“丝状支原体簇”的其他成员或密切相关的支原体无反应。经实验接触感染丝状支原体丝状亚种SC的奶牛在35天内产生了针对P72的体液反应。P72是丝状支原体丝状亚种SC的一种特异性抗原性膜脂蛋白，有潜力用于开发诊断试剂。它似乎属于“丝状支原体簇”的脂蛋白家族。
