SUMO modification of the ubiquitin-conjugating enzyme E2-25K.
Post-translational modification with small ubiquitin-related modifier (SUMO) alters the function of many proteins, but the molecular mechanisms and consequences of this modification are still poorly defined. During a screen for novel SUMO1 targets, we identified the ubiquitin-conjugating enzyme E2-25K (Hip2). SUMO attachment severely impairs E2-25K ubiquitin thioester and unanchored ubiquitin ... chain formation in vitro. Crystal structures of E2-25K(1-155) and of the E2-25K(1-155)-SUMO conjugate (E2-25K(*)SUMO) indicate that SUMO attachment interferes with E1 interaction through its location on the N-terminal helix. The SUMO acceptor site in E2-25K, Lys14, does not conform to the consensus site found in most SUMO targets (PsiKXE), and functions only in the context of an alpha-helix. In contrast, adjacent SUMO consensus sites are modified only when in unstructured peptides. The demonstration that secondary structure elements are part of SUMO attachment signals could contribute to a better prediction of SUMO targets.
Mesh Terms:
Amino Acid Sequence, Consensus Sequence, Crystallization, HeLa Cells, Humans, Molecular Sequence Data, Protein Interaction Mapping, Protein Processing, Post-Translational, Protein Structure, Secondary, SUMO-1 Protein, Ubiquitin-Conjugating Enzymes
Amino Acid Sequence, Consensus Sequence, Crystallization, HeLa Cells, Humans, Molecular Sequence Data, Protein Interaction Mapping, Protein Processing, Post-Translational, Protein Structure, Secondary, SUMO-1 Protein, Ubiquitin-Conjugating Enzymes
Nat. Struct. Mol. Biol.
Date: Mar. 01, 2005
PubMed ID: 15723079
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