CATH Classification

Domain Context

CATH Clusters

Superfamily Ubiquitin Conjugating Enzyme
Functional Family Ubiquitin-conjugating enzyme E2 D2

Enzyme Information

2.3.2.24
(E3-independent) E2 ubiquitin-conjugating enzyme.
based on mapping to UniProt P62837
S-ubiquitinyl-[E1 ubiquitin-activating enzyme]-L-cysteine + [acceptor protein]-L-lysine = [E1 ubiquitin-activating enzyme]-L-cysteine + N(6)- monoubiquitinyl-[acceptor protein]-L-lysine.
-!- The enzyme transfers a single ubiquitin directly from an ubiquitinated E1 ubiquitin-activating enzyme to itself, and on to a lysine residue of the acceptor protein without involvement of E3 ubiquitin transferases (cf. EC 2.3.2.26, EC 2.3.2.27). -!- It forms a labile ubiquitin adduct in the presence of E1, ubiquitin, and Mg(2+)-ATP and catalyzes the conjugation of ubiquitin to protein substrates, independently of E3. -!- This transfer has only been observed with small proteins. -!- In vitro a transfer to small acceptors (e.g. L-lysine, N-acetyl-L- lysine methyl ester) has been observed.
2.3.2.23
E2 ubiquitin-conjugating enzyme.
based on mapping to UniProt P62837
S-ubiquitinyl-[E1 ubiquitin-activating enzyme]-L-cysteine + [E2 ubiquitin-conjugating enzyme]-L-cysteine = [E1 ubiquitin-activating enzyme]-L-cysteine + S-ubiquitinyl-[E2 ubiquitin-conjugating enzyme]-L- cysteine.
-!- The E2 ubiquitin-conjugating enzyme acquires the activated ubquitin from the E1 ubiquitin-activating enzyme (EC 6.2.1.45) and binds it via a transthioesterification reaction to itself. -!- In the human enzyme the catalytic center is located at Cys-87 where ubiquitin is bound via its C-terminal glycine in a thioester linkage. -!- Formerly EC 6.3.2.19.

UniProtKB Entries (1)

Q96BH1
RNF25_HUMAN
Homo sapiens
E3 ubiquitin-protein ligase RNF25

PDB Structure

PDB 5D1M
External Links
Method X-RAY DIFFRACTION
Organism
Primary Citation
Insights into Ubiquitination from the Unique Clamp-like Binding of the RING E3 AO7 to the E2 UbcH5B.
Li, S., Liang, Y.H., Mariano, J., Metzger, M.B., Stringer, D.K., Hristova, V.A., Li, J., Randazzo, P.A., Tsai, Y.C., Ji, X., Weissman, A.M.
J.Biol.Chem.
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