Structure of the yeast Bre1 RING domain

Monoubiquitination of histone H2B at Lys123 in yeast plays a critical role in regulating transcription, mRNA export, DNA replication, and the DNA damage response. The RING E3 ligase, Bre1, catalyzes monoubiquitination of H2B in concert with the E2 ubiquitin‐conjugating enzyme, Rad6. The crystal structure of a C‐terminal fragment of Bre1 shows that the catalytic RING domain is preceded by an N‐terminal helix that mediates coiled‐coil interactions with a crystallographically related monomer. Homology modeling suggests that the human homologue of Bre1, RNF20/RNF40, heterodimerizes through similar coiled‐coil interactions. Proteins 2015; 83:1185–1190. © 2015 The Authors. Proteins: Structure, Function, and Bioinformatics Published by Wiley Periodicals, Inc.