Department of Biochemistry and Molecular Biology, State University of New York Upstate Medical University, 750 East Adams Street, Syracuse, NY, 13210, USA.
Sci Rep. 2017 Mar 13;7:44388. doi: 10.1038/srep44388.
Domain swapping is the process by which identical proteins exchange reciprocal segments to generate dimers. Here we introduce induced domain swapping (INDOS) as a mechanism for regulating protein function. INDOS employs a modular design consisting of the fusion of two proteins: a recognition protein that binds a triggering molecule, and a target protein that undergoes a domain swap in response to binding of the triggering ligand. The recognition protein (FK506 binding protein) is inserted into functionally-inactivated point mutants of two target proteins (staphylococcal nuclease and ribose binding protein). Binding of FK506 to the FKBP domain causes the target domain to first unfold, then refold via domain swap. The inactivating mutations become 'swapped out' in the dimer, increasing nuclease and ribose binding activities by 100-fold and 15-fold, respectively, restoring them to near wild-type values. INDOS is intended to convert an arbitrary protein into a functional switch, and is the first example of rational design in which a small molecule is used to trigger protein domain swapping and subsequent activation of biological function.
结构域交换是指相同蛋白质交换相互对应的片段以形成二聚体的过程。在这里，我们提出诱导结构域交换（INDOS）作为一种调节蛋白质功能的机制。INDOS 采用模块化设计，由两种蛋白质融合而成：一种是识别蛋白质，它能结合触发分子；另一种是靶蛋白，它能在结合触发配体后发生结构域交换。将 FK506 结合蛋白插入到两个靶蛋白（葡萄球菌核酸酶和核糖结合蛋白）的功能失活点突变体中。FK506 与 FKBP 结构域的结合导致靶结构域首先展开，然后通过结构域交换重新折叠。在二聚体中，失活突变被“交换”出去，分别使核酸酶和核糖结合活性增加 100 倍和 15 倍，使其恢复到接近野生型水平。INDOS 旨在将任意蛋白质转化为功能性开关，是第一个使用小分子触发蛋白质结构域交换和随后激活生物功能的理性设计的例子。
