2h0d

From Proteopedia

Structure of a Bmi-1-Ring1B Polycomb group ubiquitin ligase complex

Overview

Polycomb group proteins Bmi-1 and Ring1B are core subunits of the PRC1, complex, which plays important roles in the regulation of Hox gene, expression, X-chromosome inactivation, tumorigenesis, and stem cell, self-renewal. The RING finger protein Ring1B is an E3 ligase that, participates in the ubiquitination of lysine 119 of histone H2A, and the, binding of Bmi-1 stimulates the E3 ligase activity. We have mapped the, regions of Bmi-1 and Ring1B required for efficient ubiquitin transfer and, determined a 2.5-A structure of the Bmi-1-Ring1B core domain complex. The, structure reveals that Ring1B "hugs" Bmi-1 through extensive RING domain, contacts and its N-terminal tail wraps around Bmi-1. The two regions of, interaction have a synergistic effect on the E3 ligase activity. Our, analyses suggest a model where the Bmi-1-Ring1B complex stabilizes the, interaction between the E2 enzyme and the nucleosomal substrate to allow, efficient ubiquitin transfer.

About this Structure

2H0D is a Protein complex structure of sequences from Homo sapiens with ZN as ligand. Full crystallographic information is available from OCA.

Reference

Structure of a Bmi-1-Ring1B polycomb group ubiquitin ligase complex., Li Z, Cao R, Wang M, Myers MP, Zhang Y, Xu RM, J Biol Chem. 2006 Jul 21;281(29):20643-9. Epub 2006 May 18. PMID:16714294

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