|Protein Name||Ubiquitin-like modifier-activating enzyme 5|
|Ref Sequence Id||NP_001094537.1|
|Amino Acid Lenth||404|
|Protein Existence Status||Reviewed: Experimental evidence at transcript level|
|Protein Function||Key mediators of chain assembly; able to govern the switch from ubiquitin chain initiation to elongation, regulate the processivity of chain formation and establish the topology of assembled chains, determine the consequences of ubiquitylation for the modified proteins; E2s have an active role in determining the length and topology of ubiquitin chains and the processivity of the chain assembly reaction; E2 strongly influences the selection of the correct modifier, ubiquitin, and a suitable E3|
|Biochemical Properties||As found in humans, active E2s possess a core ubiquitinconjugating (UBC) domain, which contains the catalytic Cys residue and interacts with E1s; ubiquitinylated E2s engage E3s to catalyse substrate ubiquitylation; a single E2 can interact with several different E3s; interactions between E2s and E3s are usually weak, with dissociation constants in the micromolar range; E2s bind cofactors that influence their localization, activity or specificity; E2s exist mainly as E2~Ub conjugates and are therefore poised to react - E2~Ub conjugates have low rates of Ub transfer in the absence of an E3 ligase|
|Significance in milk||integral components of the ubiquitin proteasome system in milk|
|PTMs||Ubiquitylation on lysine residues; sumolylation|
|Significance of PTMs||SUMO can also act as a covalent modulator of E2 activity|
|Bibliography||1. VanDemark, A. P., Hofmann, R. M., Tsui, C., Pickart, C. M., & Wolberger, C. (2001). Molecular insights into polyubiquitin chain assembly: Crystal structure of the Mms2/Ubc13 heterodimer. Cell, 105(6), 711–720. https://doi.org/10.1016/S0092-8674(01)00387-7. |
2. Yin, Q., Lin, S.-C., Lamothe, B., Lu, M., Lo, Y.-C., Hura, G., … Wu, H. (2009). E2 interaction and dimerization in the crystal structure of TRAF6. Nature Structural & Molecular Biology, 16(6), 658–666. https://doi.org/10.1038/nsmb.1605.
3. Skowyra, D., Craig, K. L., Tyers, M., Elledge, S. J., & Harper, J. W. (1997). F-box proteins are receptors that recruit phosphorylated substrates to the SCF ubiquitin-ligase complex. Cell, 91(2), 209–219. https://doi.org/10.1016/S0092-8674(00)80403-1.
4. Ozkan, E., Yu, H., & Deisenhofer, J. (2005). Mechanistic insight into the allosteric activation of a ubiquitin-conjugating enzyme by RING-type ubiquitin ligases. Proceedings of the National Academy of Sciences of the United States of America, 102(52), 18890–18895. https://doi.org/10.1073/pnas.0509418102.
5. Lin, Y., Hwang, W. C., & Basavappa, R. (2002). Structural and functional analysis of the human mitotic-specific ubiquitin-conjugating enzyme, UbcH10. The Journal of Biological Chemistry, 277(24), 21913–21921. https://doi.org/10.1074/jbc.M109398200.