Photochemical uncaging techniques use light to release active molecules from otherwise inert compounds. Here we expand this class of techniques by demonstrating the mechanical uncaging of a reactive species within a single protein. We proved this novel technique by capturing the regiospecific reaction between a thiol and a vicinal disulfide bond. We designed a protein that includes a caged cyst...

The majority of eukaryotic secretory and membrane proteins contain disulfide bonds, which are strongly conserved within protein families because of their crucial role in folding or function. The exact role of these disulfide bonds during folding is unclear. Using virus-driven evolution we generated a viral glycoprotein variant, which is functional despite the lack of an absolutely conserved dis...

Using magnetic relaxation dispersion (MRD), we have previously shown that the four internal water molecules in bovine pancreatic trypsin inhibitor (BPTI) exchange with bulk water on time scales between 10(-8) and 10(-4) s at room temperature. Because this exchange is controlled by the protein structure, internal water molecules can be used to probe rare conformational fluctuations. Here, we rep...

Extracellular vesicles (EVs) play a critical role in intercellular communication by transferring microRNAs, lipids, and proteins to neighboring cells. Sortilin, a sorting receptor that directs target proteins to the secretory or endocytic compartments of cells, is found in both EVs and cells. In many human diseases, including cancer and cardiovascular disorders, sortilin expression levels are a...

Toll-like receptor 7 (TLR7) an innate immune sensor for microbial RNA, erroneously responds to self-derived RNA. To avoid autoimmune responses, TLR7 is suggested to be silenced until the N-terminal half of the TLR7 ectodomain (TLR7N) is cleaved off. Resultant truncated TLR7 (TLR7C) is thought to signal microbial RNA. We here show that TLR7N remains associated with TLR7C through a disulfide bond...

Many eukaryotic proteins are tethered to the plasma membrane via glycosylphosphatidylinositol (GPI). GPI transamidase is localized in the endoplasmic reticulum and mediates post-translational transfer of preformed GPI to proteins bearing a carboxyl-terminal GPI attachment signal. Mammalian GPI transamidase is a multimeric complex consisting of at least five subunits. Here we report that two sub...

The copper chaperone for superoxide dismutase 1 (Ccs1) provides an important cellular function against oxidative stress. Ccs1 is present in the cytosol and in the intermembrane space (IMS) of mitochondria. Its import into the IMS depends on the Mia40/Erv1 disulfide relay system, although Ccs1 is, in contrast to typical substrates, a multidomain protein and lacks twin Cx(n)C motifs. We report on...

It is known that cyanide is converted to thiocyanate in the presence of the enzyme rhodanese. The enzyme is activated by sulfur transfer from an appropriate sulfur donor. The activated enzyme then binds cyanide and transfers the sulfur atom to cyanide to form thiocyanate. This project began as an exploration of the ability of disulfides to act as sulfur donors in the rhodanese-mediated detoxifi...