Ruehl W W, Marrs C F, Fernandez R, Falkow S, Schoolnik G K
Department of Pathology, Stanford University, California.
J Exp Med. 1988 Sep 1;168(3):983-1002. doi: 10.1084/jem.168.3.983.
Pilins composed of the alpha or beta pilins of Moraxella bovis strain Epp63 were purified, subjected to chemical or enzymatic cleavage, and the resulting fragments sequenced by automated Edman degradation. alpha Pilin was found to be a 155-amino-acid polypeptide with a single intramolecular disulfide bridge. The beta pilin amino acid sequence substantiated the previously reported structure derived from the beta pilin gene DNA sequence, and indicated that the alpha and beta pilins of this strain are approximately 70% homologous. DNA hybridization studies of genomic DNA from the alpha- and beta-piliated variants of strain Epp63 indicated that the expression of the two pilin types was governed by an oscillating mechanism of chromosomal rearrangement. The alpha and beta pili were evaluated serologically and found to exhibit approximately 50% shared antigenicity, indicating that regions of conserved and heterologous sequence specify both type-specific and crossreacting epitopes. The pathogenicity of the alpha- and beta-piliated variants was studied by ocular inoculation of calves eyes; beta-piliated organisms were significantly more infectious than alpha-piliated organisms, indicating that beta pili confer, or are associated with, a relative advantage during the first stages of ocular infection. Preliminary analysis of other M. bovis strains suggests that each strain produces two types of pilin, and that this property may be characteristic of the species.
纯化了由牛莫拉菌Epp63株的α或β菌毛蛋白组成的菌毛蛋白，对其进行化学或酶切，然后通过自动埃德曼降解法对产生的片段进行测序。发现α菌毛蛋白是一种含有单个分子内二硫键的155个氨基酸的多肽。β菌毛蛋白的氨基酸序列证实了先前从β菌毛蛋白基因DNA序列推导的结构，并表明该菌株的α和β菌毛蛋白约70%同源。对Epp63株的α菌毛和β菌毛变体的基因组DNA进行的DNA杂交研究表明，两种菌毛蛋白类型的表达受染色体重排的振荡机制控制。对α和β菌毛进行了血清学评估，发现它们表现出约50%的共同抗原性，这表明保守和异源序列区域既决定了型特异性表位，也决定了交叉反应表位。通过对犊牛眼睛进行眼内接种研究了α菌毛和β菌毛变体的致病性；β菌毛生物比α菌毛生物的传染性明显更强，这表明β菌毛在眼部感染的最初阶段赋予了相对优势或与之相关。对其他牛莫拉菌菌株的初步分析表明，每个菌株都产生两种类型的菌毛蛋白，并且这种特性可能是该物种的特征。
