Chimeric 14-3-3 proteins for unraveling interactions with intrinsically disordered partners

Sci Rep. 2017 Sep 20;7(1):12014. doi: 10.1038/s41598-017-12214-9.

Abstract

In eukaryotes, several "hub" proteins integrate signals from different interacting partners that bind through intrinsically disordered regions. The 14-3-3 protein hub, which plays wide-ranging roles in cellular processes, has been linked to numerous human disorders and is a promising target for therapeutic intervention. Partner proteins usually bind via insertion of a phosphopeptide into an amphipathic groove of 14-3-3. Structural plasticity in the groove generates promiscuity allowing accommodation of hundreds of different partners. So far, accurate structural information has been derived for only a few 14-3-3 complexes with phosphopeptide-containing proteins and a variety of complexes with short synthetic peptides. To further advance structural studies, here we propose a novel approach based on fusing 14-3-3 proteins with the target partner peptide sequences. Such chimeric proteins are easy to design, express, purify and crystallize. Peptide attachment to the C terminus of 14-3-3 via an optimal linker allows its phosphorylation by protein kinase A during bacterial co-expression and subsequent binding at the amphipathic groove. Crystal structures of 14-3-3 chimeras with three different peptides provide detailed structural information on peptide-14-3-3 interactions. This simple but powerful approach, employing chimeric proteins, can reinvigorate studies of 14-3-3/phosphoprotein assemblies, including those with challenging low-affinity partners, and may facilitate the design of novel biosensors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 14-3-3 Proteins / chemistry*
  • 14-3-3 Proteins / genetics
  • 14-3-3 Proteins / metabolism
  • Amino Acid Sequence
  • Crystallography, X-Ray
  • Humans
  • Intrinsically Disordered Proteins / chemistry*
  • Intrinsically Disordered Proteins / genetics
  • Intrinsically Disordered Proteins / metabolism
  • Models, Molecular
  • Multiprotein Complexes / chemistry
  • Multiprotein Complexes / metabolism
  • Peptides / chemistry
  • Peptides / genetics
  • Peptides / metabolism
  • Phosphopeptides / chemistry*
  • Phosphopeptides / genetics
  • Phosphopeptides / metabolism
  • Phosphorylation
  • Protein Binding
  • Protein Conformation
  • Protein Multimerization
  • Recombinant Fusion Proteins / chemistry*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism

Substances

  • 14-3-3 Proteins
  • Intrinsically Disordered Proteins
  • Multiprotein Complexes
  • Peptides
  • Phosphopeptides
  • Recombinant Fusion Proteins