Journal
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Volume 102, Issue 52, Pages 18890-18895Publisher
NATL ACAD SCIENCES
DOI: 10.1073/pnas.0509418102
Keywords
mechanism; E2 enzymes; E3 enzymes
Categories
Funding
- NIGMS NIH HHS [R01 GM061542, GM61542] Funding Source: Medline
Ask authors/readers for more resources
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, 137A, 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.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available