Investigation of the three-dimensional architecture of the collagen adhesin EmaA of Aggregatibacter actinomycetemcomitans by electron tomography.
Investigation of the three-dimensional architecture of the collagen adhesin EmaA of Aggregatibacter actinomycetemcomitans by electron tomography.
复制标题
通过电子断层扫描研究 Aggregatibacter actinomycetemcomitans 的胶原粘附素 EmaA 的三维结构。
DOI：
10.1128/jb.00563-09
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发表时间：
2009
影响因子：
3.2
通讯作者：
Ruiz,Teresa
中科院分区：
文献类型：
--
作者：
Yu,Chunxiao;Mintz,KeithP;Ruiz,Teresa
The periodontal pathogenAggregatibacter actinomycetemcomitansdisplays on the bacterial surface a nonfimbrial adhesin, EmaA, which is required for collagen binding. In this study, electron tomography was used to characterize the three-dimensional (3D) architecture of this adhesin. The antenna-like surface appendages, corresponding to EmaA, were found to be composed of an ellipsoidal domain capping a rod-like domain that adopts either a straight or a bent conformation at various positions along the length. The most common flexible point along the length of the EmaA appendage was localized 29.4 nm away from the distal end. One-fifth of the appendages were straight and the remaining showed angles distributed between 140° and 170° at this location. Deletion analysis mapped this bend to amino acids 611 to 640 of the protein sequence. The 3D structure of the collagen binding domain of EmaA was generated by alignment and averaging of 9 subvolumes of the adhesin extracted from tomograms. The structure contains three subdomains: a globular structure with a diameter of ∼5 nm and a cylindrical domain (∼4.4 nm by 5.8 nm) separated by a linker region with a diameter of ∼3 nm, followed by a cylindrical domain (∼4.6 nm by 6.6 nm). This is the first 3D structure of a trimeric autotransporter protein ofA. actinomycetemcomitans.
