2esk
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Human Ubiquitin-Conjugating Enzyme (E2) UbcH5b, wild-type
OverviewOverview
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.
About this StructureAbout this Structure
2ESK is a Single protein structure of sequence from Homo sapiens. Active as Ubiquitin--protein ligase, with EC number 6.3.2.19 Full crystallographic information is available from OCA.
ReferenceReference
Mechanistic insight into the allosteric activation of a ubiquitin-conjugating enzyme by RING-type ubiquitin ligases., Ozkan E, Yu H, Deisenhofer J, Proc Natl Acad Sci U S A. 2005 Dec 27;102(52):18890-5. Epub 2005 Dec 19. PMID:16365295
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