親密素和侵襲素是致病性格蘭氏陰性菌產生的毒素因子,，具有重要的臨床病理意義。它們包含負責粘附宿主細胞的C末端的膜外信使結構域和插入細胞外膜的N末端β結構域,。5月31日Cell雜志子刊Structure在線發(fā)表了Fairman等人的研究論文，進一步揭示了其結構的奧秘。

研究者確定了E.coli大腸桿菌親密素β結構域的邊界,，并利用這一信息解析了它的結構,，以及Y型假結核病侵襲素的β結構域的結構。研究者獲得了單聚體β結構域晶體,，研究顯示過去被認為是β結構域的一部分蛋白結構實際上也包括了信使結構域的一部分,。

此外，基于高度保守的親密素和侵襲素β結構域的邊界信息,，研究者還確定了146個親密素/侵襲素家族的非冗余,、典型性成員。他們還結合這些序列信息和蛋白結構數(shù)據(jù),，發(fā)現(xiàn)并作圖描繪了β結構域內在進化上保守的氨基酸殘基序列,。(生物谷bioon.com)

doi:10.1016/j.cell.2011.10.017
PMC:
PMID:
Crystal Structures of the Outer Membrane Domain of Intimin and Invasin from Enterohemorrhagic E. coli and Enteropathogenic Y. pseudotuberculosis

James W. Fairman, Nathalie Dautin, Damian Wojtowicz, et al.

Summary

Intimins and invasins are virulence factors produced by pathogenic Gram-negative bacteria. They contain C-terminal extracellular passenger domains that are involved in adhesion to host cells and N-terminal β domains that are embedded in the outer membrane. Here, we identify the domain boundaries of an E. coli intimin β domain and use this information to solve its structure and the β domain structure of a Y. pseudotuberculosis invasin. Both β domain structures crystallized as monomers and reveal that the previous range of residues assigned to the β domain also includes a protease-resistant domain that is part of the passenger. Additionally, we identify 146 nonredundant representative members of the intimin/invasin family based on the boundaries of the highly conserved intimin and invasin β domains. We then use this set of sequences along with our structural data to find and map the evolutionarily constrained residues within the β domain.