2ESO: Human Ubiquitin-conjugating Enzyme (e2) Ubch5b Mutant Ile37ala

Ubiquitin-conjugating enzymes (E2s) collaborate with the ubiquitin-activating enzyme (E1) and ubiquitin ligases (E3s) to attach ubiquitin to target proteins. RING-containing E3s simultaneously bind to E2s and substrates, bringing them into close proximity and thus facilitating ubiquitination. We show herein that, although the E3-binding site on the human E2 UbcH5b is distant from its active site, two RING-type minimal E3 modules lacking substrate-binding functions greatly stimulate the rate of ubiquitin release from the UbcH5b-ubiquitin thioester. Using statistical coupling analysis and mutagenesis, we identify and characterize clusters of coevolving and functionally linked residues within UbcH5b that span its E3-binding and active sites. Several UbcH5b mutants are defective in their stimulation by E3s despite their abilities to bind to these E3s, to form ubiquitin thioesters, and to release ubiquitin at a basal rate. One such mutation, I37A, is distant from both the active site and the E3-binding site of UbcH5b. Our studies reveal structural determinants for communication between distal functional sites of E2s and suggest that RING-type E3s activate E2s allosterically.
PDB ID: 2ESODownload
MMDB ID: 36477
PDB Deposition Date: 2005/10/26
Updated in MMDB: 2005/12
Experimental Method:
x-ray diffraction
Resolution: 1.5  Å
Source Organism:
Similar Structures:
Biological Unit for 2ESO: monomeric; determined by author
Molecular Components in 2ESO
Label Count Molecule
Protein (1 molecule)
Ubiquitin-conjugating Enzyme E2 D2(Gene symbol: UBE2D2)
Molecule annotation
* Click molecule labels to explore molecular sequence information.

Citing MMDB