期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1992
卷号：89
期号：18
页码：8532-8536
DOI：10.1073/pnas.89.18.8532
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Protein G, a bacterial cell-wall protein with high affinity for the constant region of IgG (IgGFc) antibodies, contains homologous repeats responsible for the interaction with IgGFc. A synthetic peptide corresponding to an 11-amino acid-long sequence in the COOH-terminal region of the repeats was found to bind to IgGFc and block the interaction with protein G. Moreover, two other IgGFc-binding bacterial proteins (proteins A and H), which do not contain any sequences homologous to the peptide, were also inhibited in their interactions with IgGFc by the peptide. Finally, a decapeptide based on a sequence in IgGFc blocked the binding of all three proteins to IgGFc. This unusually clear example of convergent evolution emphasizes the complexity of protein-protein interactions and suggests that bacterial surface-protein interaction with host protein adds selective advantages to the microorganism.
