FIGURE 1.

Sequence and structure of PCBP2 KH1-KH2. A, domain structure of PCBP2. Similar domain structures are observed in other PCBPs. B, sequence alignment of the KH1-KH2 domains from human PCBPs. Secondary structures for PCBP2 KH1-KH2 were based on the NMR structure. Residues that define the hydrophobic interfaces for KH1-KH2 interaction are marked with ^* signs above the one-letter codes. The conserved arginine residues involved in specific recognition of two consecutive cytosine bases are marked with # signs. C, left: backbone traces of the NMR ensemble of the 12 lowest-energy conformers of PCBP2 KH1-KH2. The orange ovals indicate the three less well-defined loop regions: the variable loops within the KH1 and KH2 domains, and the linker between the two domains. Middle and right, two different views of a ribbon presentation of the lowest energy structure of PCBP2 KH1-KH2. The KH1 and KH2 domains are colored blue and red, respectively, the linker is colored green. The secondary structural elements are labeled.