STRUCTURE OF THE IGG-BINDING REGIONS OF STREPTOCOCCAL PROTEIN-G
STRUCTURE OF THE IGG-BINDING REGIONS OF STREPTOCOCCAL PROTEIN-G
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DOI：
10.1002/j.1460-2075.1986.tb04398.x
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发表时间：
1986-07-01
期刊：
影响因子：
11.4
通讯作者：
LINDBERG, M
中科院分区：
文献类型：
--
作者：
GUSS, B;ELIASSON, M;LINDBERG, M
通过分子克隆的方法从链球菌G148中分离出编码IgG结合蛋白G的基因。一个含有1.5 kb插入片段的亚克隆在大肠杆菌中产生了一个功能性产物。亲和纯化的多肽的蛋白质分析显示两个基因产物，但小于蛋白G自发释放的链球菌，但具有相同的IgG结合特性。插入片段的完整核苷酸序列揭示了可能通过不同大小片段的重复进化的重复结构。推导的氨基酸序列揭示了一个开放的阅读框架延伸整个插入，终止于TAA终止密码子。通过N-末端氨基酸测定分析两个基因产物，表明在E. coli中进行翻译起始，以产生两种产物。基于这些结果，表达并分析了几种截短的基因构建体。结果表明，链球菌G蛋白的C-末端部分由三个IgG结合域，随后是一个区域，该区域将蛋白质锚定到细胞表面。与链球菌M蛋白和葡萄球菌蛋白A的结构和功能进行了比较。
The gene encoding the IgG-binding protein G from Streptococcus G148 was isolated by molecular cloning. A subclone containing a 1.5-kb insert gave a functional product in Escherichia coli. Protein analysis of affinity-purified polypeptides revealed two gene products, but smaller than protein G spontaneously released from streptococci, but with identical IgG-binding properties. The complete nucleotide sequence of the insert revealed a repeated structure probably evolved through duplications of fragments of different sizes. The deduced amino acid sequence revealed an open reading frame extending throughout the insert, terminating in a TAA stop codon. Analysis of the two gene products by N-terminal amino acid determination suggests that two different TTG codons are recognized in E. coli for initiation of translation to yield the two products. Based on these results several truncated gene constructions were expressed and analyzed. The results suggest that the C-terminal part of streptococcal protein G consists of three IgG-binding domains followed by a region which anchors the protein to the cell surface. Structural and functional comparisons with streptococcal M protein and staphylococcal protein A have been made.