PDBsum entry 2mql

RNA binding protein

PDB id: 2mql

Contents

Protein chain

105 a.a.

References listed in PDB file

Key reference

• Title: The signature of the five-Stranded vrrm fold defined by functional, Structural and computational analysis of the hnrnp l protein.
• Authors: M.Blatter, S.Dunin-Horkawicz, I.Grishina, C.Maris, S.Thore, T.Maier, A.Bindereif, J.M.Bujnicki, F.H.Allain.
• Ref.: J Mol Biol, 2015, 427, 3001-3022. [DOI no: 10.1016/j.jmb.2015.05.020]
• PubMed id: 26051023

Abstract

The RNA recognition motif (RRM) is the far most abundant RNA binding domain. In addition to the typical β1α1β2β3α2β4 fold, various sub-structural elements have been described and reportedly contribute to the high functional versatility of RRMs. The heterogeneous nuclear ribonucleoprotein L (hnRNP L) is a highly abundant protein of 64kDa comprising four RRM domains. Involved in many aspects of RNA metabolism, hnRNP L specifically binds to RNAs containing CA repeats or CA-rich clusters. However, a comprehensive structural description of hnRNP L including its sub-structural elements is missing. Here, we present the structural characterization of the RRM domains of hnRNP L and demonstrate their function in repressing exon 4 of SLC2A2. By comparison of the sub-structural elements between the two highly similar paralog families of hnRNP L and PTB, we defined signatures underlying interacting C-terminal coils (ICCs), the RRM34 domain interaction and RRMs with a C-terminal fifth β-strand, a variation we denoted vRRMs. Furthermore, computational analysis revealed new putative ICC-containing RRM families and allowed us to propose an evolutionary scenario explaining the origins of the ICC and fifth β-strand sub-structural extensions. Our studies provide insights of domain requirements in alternative splicing mediated by hnRNP L and molecular descriptions for the sub-structural elements. In addition, the analysis presented may help to classify other abundant RRM extensions and to predict structure-function relationships.