Xenopus poly(A) binding protein: functional domains in RNA binding and protein-protein interaction.
Subsets of the four RNA binding domains (RBD 1 to 4) in the Xenopus poly-adenylate binding protein (PABP) have distinct affinities and specificities for RNA. RBDs 1 plus 2 exhibit RNA affinity and selectivity equal to the wild-type (WT) protein. RBDs 3 plus 4 have distinct selectivity and about ten-fold reduced affinity for A23, and the isolated RBDs 2 or 3 or 4 exhibit about 100-fold reduced affinity for A23 in comparison to WT. For the full-length protein, independent RNA contacts have been mapped by UV crosslinking with RBDs 1/2 and RBDs 3/4. The carboxy-terminal, non-RBD portion of the protein does not contribute to RNA affinity or selectivity, but confers homodimerization activity on PABP. RBDs 3 and 4 cooperate with the C terminus to gain poly(A) organizing activity, i.e. the ability to form an RNP with multiple, regularly spaced copies of PABP on a poly(A) substrate.
Kühn
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Institut für Biochemie und Molekulare Zellbiologie, Gottingen, Germany.
Pieler
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T
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D003432:Cross-Linking Reagents; D004247:DNA / Q000235:genetics; D008969:Molecular Sequence Data; D015394:Molecular Structure; D039102:Poly(A)-Binding Proteins; D011485:Protein Binding; D012313:RNA / Q000235:genetics / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014466:Ultraviolet Rays; D014981:Xenopus
D003432:Cross-Linking Reagents; D039102:Poly(A)-Binding Proteins; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D012313:RNA; D004247:DNA