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：2012
卷号：109
期号：12
页码：4586-4591
DOI：10.1073/pnas.1202051109
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Integrin X{beta}2 functions as complement receptor for iC3b and mediates recognition and phagocytosis of pathogens. We used negative-stain EM to examine the X{beta}2 interaction with iC3b. EM class averages of X{beta}2 in complex with iC3b define the binding sites on both the integrin and iC3b. iC3b contains C3c and thioester domain moieties linked by a long flexible linker. The binding site is on the key ring of the C3c moiety, at the interface between the MG3 and MG4 domains. Similar complexes are seen between X{beta}2 and the C3c fragment. X{beta}2 binds through the X I domain, on the face known to bear the metal ion-dependent adhesion site, at the opposite end of the I domain from its site of insertion in the {beta}-propeller domain.
