Biomedical Sciences Research Complex and School of Biology, University of St Andrews, St Andrews, KY16 9ST, United Kingdom.
John Innes Centre, Department of Biological Chemistry, Norwich Research Park, Norwich, NR4 7UH, United Kingdom.
Protein Sci. 2018 Sep;27(9):1651-1660. doi: 10.1002/pro.3478. Epub 2018 Sep 25.
An increasing number of surface-associated proteins identified in Gram-positive bacteria are characterized by intramolecular cross-links in structurally conserved thioester, isopeptide, and ester domains (TIE proteins). Two classes of thioester domains (TEDs) have been predicted based on sequence with, to date, only representatives of Class I structurally characterized. Here, we present crystal structures of three Class II TEDs from Bacillus anthracis, vancomycin-resistant Staphylococcus aureus, and vancomycin-resistant Enterococcus faecium. These proteins are structurally distinct from Class I TEDs due to a β-sandwich domain that is inserted into the conserved TED fold to form a slipknot structure. Further, the B. anthracis TED domain is presented in the context of a full-length sortase-anchored protein structure (BaTIE). This provides insight into the three-dimensional arrangement of TIE proteins, which emerge as very abundant putative adhesins of Gram-positive bacteria.
越来越多在革兰氏阳性菌中发现的表面相关蛋白的特征是结构保守的硫酯、异肽和酯结构域（TIE 蛋白）中的分子内交联。根据序列，已经预测了两类硫酯结构域（TEDs），但迄今为止仅对结构特征属于 I 类的代表进行了结构表征。在这里，我们展示了来自炭疽芽孢杆菌、耐万古霉素的金黄色葡萄球菌和耐万古霉素的粪肠球菌的三种 II 类 TED 的晶体结构。这些蛋白质由于插入到保守的 TED 折叠中的β-夹心结构域而与 I 类 TED 结构明显不同，形成滑结结构。此外，还呈现了全长分选酶锚定蛋白结构（BaTIE）中的炭疽芽孢杆菌 TED 结构域。这提供了对 TIE 蛋白的三维排列的深入了解，这些蛋白作为革兰氏阳性菌中非常丰富的假定粘附素出现。
