RNA recognition via the SAM domain of Smaug

Mol Cell. 2003 Jun;11(6):1537-48. doi: 10.1016/s1097-2765(03)00178-3.

Abstract

The Nanos protein gradient in Drosophila, required for proper abdominal segmentation, is generated in part via translational repression of its mRNA by Smaug. We report here the crystal structure of the Smaug RNA binding domain, which shows no sequence homology to any previously characterized RNA binding motif. The structure reveals an unusual makeup in which a SAM domain, a common protein-protein interaction module, is affixed to a pseudo-HEAT repeat analogous topology (PHAT) domain. Unexpectedly, we find through a combination of structural and genetic analysis that it is primarily the SAM domain that interacts specifically with the appropriate nanos mRNA regulatory sequence. Therefore, in addition to their previously characterized roles in protein-protein interactions, some SAM domains play crucial roles in RNA binding.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Consensus Sequence
  • Conserved Sequence
  • Crystallography, X-Ray
  • Drosophila
  • Drosophila Proteins / chemistry*
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism*
  • Models, Molecular
  • Molecular Sequence Data
  • Mutation
  • Protein Structure, Secondary
  • Protein Structure, Tertiary
  • RNA / metabolism*
  • RNA-Binding Proteins / chemistry*
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism*
  • Repressor Proteins / chemistry*
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism*
  • Sequence Homology, Amino Acid
  • Static Electricity

Substances

  • Drosophila Proteins
  • RNA-Binding Proteins
  • Repressor Proteins
  • smg protein, Drosophila
  • RNA

Associated data

  • PDB/10XJ