Two singular types of CCCH tandem zinc finger in Nab2p contribute to polyadenosine RNA recognition.

Santiago Martínez-Lumbreras, Clara M Santiveri, Yasmina Mirassou, Silvia Zorrilla, José Manuel Pérez-Cañadillas

Structure (London, England : 1993) 2013 Oct 8

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The seven C-terminal CCCH-type zinc fingers of Nab2p bind the poly(A) tail of mRNA (∼A25). Using NMR, we demonstrated that the first four (Zf1-Zf4) contain two structurally independent tandems (TZF12 and TZF34) and bind A12 with moderate affinity (KD = 2.3 μM). Nab2p TZF12 contains a long α helix that contacts the zinc fingers Zf1 and Zf2 to arrange them similarly to Zf6-7 in the Nab2p Zf5-7 structure. Nab2p TZF34 exhibits a distinctive two-fold symmetry of the zinc centers with mutual recognition of histidine ligands. Our mutagenesis and NMR data demonstrate that the α helix of TZF12 and Zf3 of TZF34 define the RNA-binding interface, while Zf1, Zf2, and Zf4 seem to be excluded. These results further our understanding of polyadenosine RNA recognition by the CCCH domain of Nab2p. Moreover, we describe a hypothetical mechanism for controlling poly(A) tail length with specific roles for TZF12, TZF34, and Zf5-7 domains. Copyright © 2013 Elsevier Ltd. All rights reserved.

Citation

Santiago Martínez-Lumbreras, Clara M Santiveri, Yasmina Mirassou, Silvia Zorrilla, José Manuel Pérez-Cañadillas. Two singular types of CCCH tandem zinc finger in Nab2p contribute to polyadenosine RNA recognition. Structure (London, England : 1993). 2013 Oct 8;21(10):1800-11