RUN Domain Containing Protein 2B (RUNDC2B)

RUNDC2B, Contains 1 RUN domain. The RPIPx RUN domain, interacted specifically with Rap2B in vitro in a nucleotide-dependent manner. The crystal structure of the RPIPx RUN domain was determined at 2.0Å of resolution by the multiwavelength anomalous dispersion (MAD) method. The RPIPx RUN domain comprises eight anti-parallel α-helices, which form an extensive hydrophobic core, followed by an extended segment. The residues in the core region are highly conserved, suggesting the conservation of the RUN domain-fold among the RUN domain-containing proteins. The residues forming a positively charged surface are conserved between RPIP8 and its homologs, suggesting that this surface is important for Rap2 binding. In the crystal the putative Rap2 binding site of the RPIPx RUN domain interacts with the extended segment in a segment-swapping manner.