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7153362 
Journal Article 
The Cullin-RING E3 ubiquitin ligase CRL4-DCAF1 complex dimerizes via a short helical region in DCAF1 
Ahn, J; Novince, Z; Concel, J; Byeon, CH; Makhov, AM; Byeon, IJ; Zhang, P; Gronenborn, AM; , 
2011 
Yes 
Biochemistry
ISSN: 0006-2960
EISSN: 1520-4995 
English 
21226479 
The cullin4A-RING E3 ubiquitin ligase (CRL4) is a multisubunit protein complex, comprising cullin4A (CUL4), RING H2 finger protein (RBX1), and DNA damage-binding protein 1 (DDB1). Proteins that recruit specific targets to CRL4 for ubiquitination (ubiquitylation) bind the DDB1 adaptor protein via WD40 domains. Such CRL4 substrate recognition modules are DDB1- and CUL4-associated factors (DCAFs). Here we show that, for DCAF1, oligomerization of the protein and the CRL4 complex occurs via a short helical region (residues 845-873) N-terminal to DACF1's own WD40 domain. This sequence was previously designated as a LIS1 homology (LisH) motif. The oligomerization helix contains a stretch of four Leu residues, which appear to be essential for α-helical structure and oligomerization. In vitro reconstituted CRL4-DCAF1 complexes (CRL4(DCAF1)) form symmetric dimers as visualized by electron microscopy (EM), and dimeric CRL4(DCAF1) is a better E3 ligase for in vitro ubiquitination of the UNG2 substrate compared to a monomeric complex.