2PX9: The intrinsic affinity between E2 and the Cys domain of E1 in Ubiquitin-like modifications

Ubiquitin-like modifications, which are carried out by similar biochemical mechanisms, regulate nearly every aspect of cellular function. Despite the recent advancements in characterizing their enzymology, our knowledge about the dynamic processes of these modifications is still fragmentary. In this study, we have uncovered an intrinsic affinity between the SUMO E2 and the Cys domain of SUMO E1. NMR studies in combination with paramagnetic spin labeling demonstrate that this interaction is mediated by previously unknown interfaces on both E1 and E2 and places the two catalytic Cys residues of the two enzymes in close proximity. Site-directed mutagenesis and enzymatic assays indicate that the interaction is fundamentally important for the transfer of SUMO from E1 to E2. Results from this study suggest that the interaction between E2 and the Cys domain of E1 participates in guiding the E2's translocation to E1's enzymatic active site in ubiquitin-like modifications.
PDB ID: 2PX9Download
MMDB ID: 54098
PDB Deposition Date: 2007/5/14
Updated in MMDB: 2007/11
Experimental Method:
solution nmr
Source Organism:
Similar Structures:
Molecular Components in 2PX9
Label Count Molecule
Proteins (2 molecules)
Sumo-activating Enzyme Subunit 2(Gene symbol: UBA2)
Molecule annotation
Sumo-conjugating Enzyme Ubc9(Gene symbol: UBE2I)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB