AU-rich RNA-binding induces changes in the quaternary structure of AUH.
The human AU RNA binding protein/enoyl-Coenzyme A hydratase (AUH) is a 3-hydroxy-3-methylglutaconyl-CoA dehydratase in the leucine degradation pathway. It also possesses an RNA-binding activity to AUUU repeats, which involves no known conserved RNA-binding domains and is seemingly unrelated to the enzymatic activity. In this study, we performed mass spectrometric analyses to elucidate the oligomeric states of AUH in the presence and absence of RNA. With a short RNA (AUUU) or without RNA, AUH mainly exists as a trimer in solution. On the other hand, the AUH trimer dimerizes upon binding to one molecule of a long RNA containing 24 repeats of the AUUU motif, (AUUU)(24)A. AUH was crystallized with the long RNA. Although the RNA was disordered in the crystalline lattice, the AUH structure was determined as an asymmetric dimer of trimers with a kink in the alignment of the trimer axes, resulting in the formation of two clefts with significantly different sizes.
Kurimoto
Kazuki
K
RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama 230-0045, Japan.
Kuwasako
Kanako
K
Sandercock
Alan M
AM
Unzai
Satoru
S
Robinson
Carol V
CV
Muto
Yutaka
Y
Yokoyama
Shigeyuki
S
D003460:Crystallization; D004746:Enoyl-CoA Hydratase / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D013058:Mass Spectrometry; D011485:Protein Binding; D011487:Protein Conformation; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D012313:RNA / Q000737:chemistry* / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism*; D014461:Ultracentrifugation
D016601:RNA-Binding Proteins; D012313:RNA; C092554:AUH protein, human; D004746:Enoyl-CoA Hydratase