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- ******************************************
- * Ubiquitin-activating enzyme signatures *
- ******************************************
-
- Ubiquitin-activating enzyme (E1 enzyme) [1,2] activates ubiquitin by first
- adenylating with ATP its C-terminal glycine residue and thereafter linking
- this residue to the side chain of a cysteine residue in E1, yielding an
- ubiquitin-E1 thiolester and free AMP. Later the ubiquitin moiety is
- transferred to a cysteine residue on one of the many forms of ubiquitin-
- conjugating enzymes (E2).
-
- E1 is a large monomeric protein of about 110 to 115 Kd (about 1000 residues).
- In yeast it is encoded by a single gene (UBA1) while in plants and mammals
- multiple forms exist including a form which is Y-linked in mouse and some
- other mammals and which may be involved in spermatogenesis.
-
- It has been shown [3] that the last of the five cysteines that are conserved
- in the sequence of E1 from various species is the one that binds ubiquitin. We
- have developed two patterns specific for E1, the first pattern contains the
- second of the five conserved cysteines while the second pattern includes the
- active site cysteine.
-
- -Consensus pattern: K-A-C-S-G-K-F-x-P
- -Sequences known to belong to this class detected by the pattern: ALL.
- -Other sequence(s) detected in SWISS-PROT: NONE.
-
- -Consensus pattern: D-P-P-E-K-x(2)-P-[LIVM]-C-T-[LIVM]-[KRH]-x-F-P
- [C is the active site residue]
- -Sequences known to belong to this class detected by the pattern: ALL.
- -Other sequence(s) detected in SWISS-PROT: NONE.
-
- -Last update: October 1993 / Patterns and text revised.
-
- [ 1] Jentsch S., Seufert W., Hauser H.-P.
- Biochim. Biophys. Acta 1089:127-139(1991).
- [ 2] Hershko A.
- Trends Biochem. Sci. 16:265-268(1991).
- [ 3] Hatfield P.M., Vierstra R.D.
- J. Biol. Chem. 267:14799-14803(1992).
-