Lindmark H, Nilsson M, Guss B
Department of Microbiology, Swedish University of Agricultural Sciences, S-750 07 Uppsala, Sweden.
Infect Immun. 2001 May;69(5):3159-63. doi: 10.1128/IAI.69.5.3159-3163.2001.
The gene fnz from Streptococcus equi subspecies zooepidemicus encodes a cell surface protein that binds fibronectin (Fn). Fifty tested isolates of S. equi subspecies equi all contain DNA sequences with similarity to fnz. This work describes the cloning and sequencing of a gene, designated fne, with similarity to fnz from two S. equi subspecies equi isolates. The DNA sequences were found to be identical in the two strains, and sequence comparison of the fne and fnz genes revealed only minor differences. However, one base deletion was found in the middle of the fne gene and eight base pairs downstream of the altered reading frame there is a stop codon. An Fn-binding protein was purified from the growth medium of a subspecies equi culture. Determination of the NH(2)-terminal amino acid sequence and molecular mass, as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, revealed that the purified protein is the gene product of the 5'-terminal half of fne. Fn-binding activity has earlier only been found in the COOH-terminal half of FNZ. By the use of a purified recombinant protein containing the NH(2) half of FNZ, we provide here evidence that this half of the protein also harbors an Fn-binding domain.
来自马链球菌兽疫亚种的基因fnz编码一种能结合纤连蛋白（Fn）的细胞表面蛋白。对50株马链球菌马亚种分离株进行检测，发现它们都含有与fnz相似的DNA序列。这项研究描述了从两株马链球菌马亚种分离株中克隆和测序一个与fnz相似的基因，命名为fne。发现这两个菌株的DNA序列相同，fne和fnz基因的序列比较仅显示出微小差异。然而，在fne基因中部发现一个碱基缺失，在改变的阅读框下游八个碱基对处有一个终止密码子。从马亚种培养物的生长培养基中纯化出一种Fn结合蛋白。通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳判断，对其NH₂-末端氨基酸序列和分子量的测定表明，纯化的蛋白是fne 5'-末端一半的基因产物。Fn结合活性此前仅在FNZ的COOH-末端一半中发现。通过使用含有FNZ NH₂一半的纯化重组蛋白，我们在此提供证据表明该蛋白的这一半也含有一个Fn结合结构域。
