RNA recognition and self-association of CPEB4 is mediated by its tandem RRM domains.
Bottom Line: Self-association does not affect the proteins' ability to interact with RNA as demonstrated by ion mobility-mass spectrometry.Chemical shift effects measured by NMR of the apo forms of the RRM1-RRM2 samples indicate that the two domains are orientated toward each other.We propose a model of the CPEB4 RRM1-RRM2-CPE complex that illustrates the experimental data.
Affiliation: Institute for Research in Biomedicine (IRB Barcelona), Baldiri Reixac 10, Barcelona 08028, Spain.Show MeSH
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Mentions: The structure of the RRM1 domain of CPEB3, which is completely conserved when aligned to CPEB2 and 4, has been solved byNuclear Magnetic Resonance (NMR) (PDB code: 2DNL) and shows the canonical RRM domain fold of a αβ-sandwich with a β1α1β2β3α2β4 topology with the addition of two β strands immediately before the β4 strand (β4′ and β4″). Two conserved motifs, which are generally involved in RRM–RNA interactions, RNP1 and RNP2 lie in the central strands of the RRM β-sheet (18). The consensus sequence of RNP1 is (RK)-G-(FY)-(GA)-(FY)-(ILV)-X-(FY), while that of RNP2 is (ILV)-(FY)-(ILV)-X-N-L. The first RRM domain (RRM1) contains, for the most part, both RNP motifs. However, the second (RRM2), more C-terminal domain lacks the consensus sequence of an RNP1 motif. This characteristic is shared among all CPEB family members (Figure 1).
Affiliation: Institute for Research in Biomedicine (IRB Barcelona), Baldiri Reixac 10, Barcelona 08028, Spain.