Structure of the N-terminal Mlp1-binding domain of the Saccharomyces cerevisiae mRNA-binding protein, Nab2

J Mol Biol. 2008 Feb 29;376(4):1048-59. doi: 10.1016/j.jmb.2007.11.087. Epub 2007 Dec 4.

Abstract

Nuclear abundant poly(A) RNA-binding protein 2 (Nab2) is an essential yeast heterogeneous nuclear ribonucleoprotein that modulates both mRNA nuclear export and poly(A) tail length. The N-terminal domain of Nab2 (residues 1-97) mediates interactions with both the C-terminal globular domain of the nuclear pore-associated protein, myosin-like protein 1 (Mlp1), and the mRNA export factor, Gfd1. The solution and crystal structures of the Nab2 N-terminal domain show a primarily helical fold that is analogous to the PWI fold found in several other RNA-binding proteins. In contrast to other PWI-containing proteins, we find no evidence that the Nab2 N-terminal domain binds to nucleic acids. Instead, this domain appears to mediate protein:protein interactions that facilitate the nuclear export of mRNA. The Nab2 N-terminal domain has a distinctive hydrophobic patch centered on Phe73, consistent with this region of the surface being a protein:protein interaction site. Engineered mutations within this hydrophobic patch attenuate the interaction with the Mlp1 C-terminal domain but do not alter the interaction with Gfd1, indicating that this patch forms a crucial component of the interface between Nab2 and Mlp1.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Crystallography, X-Ray
  • Hydrophobic and Hydrophilic Interactions
  • Models, Molecular
  • Nuclear Proteins / chemistry*
  • Nucleocytoplasmic Transport Proteins / chemistry*
  • Phenylalanine
  • Protein Binding
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • RNA, Messenger / metabolism*
  • RNA-Binding Proteins / chemistry*
  • Saccharomyces cerevisiae / chemistry*
  • Saccharomyces cerevisiae Proteins / chemistry*
  • Solutions

Substances

  • MLP1 protein, S cerevisiae
  • NAB2 protein, S cerevisiae
  • Nuclear Proteins
  • Nucleocytoplasmic Transport Proteins
  • RNA, Messenger
  • RNA-Binding Proteins
  • Saccharomyces cerevisiae Proteins
  • Solutions
  • Phenylalanine

Associated data

  • PDB/2JPS
  • PDB/2V75
  • PDB/R2V75SF