Mar 7, 2013 · How the E1 and E2 active sites come together during thioester transfer and how Ub E1 interacts with diverse Ub E2s remains unclear. Here we present a crystal structure of a Ub E1-E2 (Ubc4)/Ub/ATP⋅Mg complex that was stabilized by induction of a disulfide bond between the E1 and E2 active sites.

Ubiquitin-activating enzymes, also known as E1 enzymes, catalyze the first step in the ubiquitination reaction, which (among other things) can target a protein for degradation via a proteasome.

Apr 22, 2021 · Here, we determine the structure of a covalently trapped E1–E2–ubiquitin thioester mimetic. Two distinct architectures of the complex are observed, one in which the Ub thioester (Ub (t))...

Jul 25, 2008 · Ubiquitin (Ub) and ubiquitin-like proteins (Ubls) are conjugated to their targets by specific cascades involving three classes of enzymes, E1, E2, and E3. Each E1 adenylates the C terminus of its cognate Ubl, forms a E1∼Ubl thioester intermediate, and ultimately generates a thioester-linked E2∼Ubl product.

Jan 14, 2021 · Ubiquitination is a sequential cascade of enzymatic reactions. First, ubiquitin (Ub) is attached to the E1 Ub-activating enzyme in an ATP-dependent manner before it is transferred to an E2...

May 16, 2016 · To monitor catalysis along these complex reaction pathways, we developed a cascading activity-based probe, UbDha. Similarly to the native Ub, upon ATP-dependent activation by the E1, UbDha can...

Here, we use phage display and mutagenesis to construct xUB-xE1 and xE1-xE2 pairs that are orthogonal to the native E1 and E2 enzymes. Our work on engineering the UB transfer cascades will enable us to use OUT to map the signal transduction networks mediated by …

Ubiquitin (Ub) signaling plays a key regulatory role in nearly every aspect of eukaryotic biology and is initiated by E1 enzymes that activate and transfer Ub to E2 Ub-conjugating enzymes.

Ubiquitin (UB) is a protein modifier that regulates many essential cellular processes. To initiate protein modification by UB, the E1 enzyme activates the C-terminal carboxylate of UB to launch its transfer through the E1-E2-E3 cascade onto target ...

Apr 22, 2021 · E1 enzymes function as gatekeepers of ubiquitin (Ub) signaling by catalyzing activation and transfer of Ub to tens of cognate E2 conjugating enzymes in a process called E1-E2 transthioesterification.