AtFKBP53: a chimeric histone chaperone with functional nucleoplasmin and PPIase domains

Nucleic Acids Res. 2020 Feb 20;48(3):1531-1550. doi: 10.1093/nar/gkz1153.

Abstract

FKBP53 is one of the seven multi-domain FK506-binding proteins present in Arabidopsis thaliana, and it is known to get targeted to the nucleus. It has a conserved PPIase domain at the C-terminus and a highly charged N-terminal stretch, which has been reported to bind to histone H3 and perform the function of a histone chaperone. To better understand the molecular details of this PPIase with histone chaperoning activity, we have solved the crystal structures of its terminal domains and functionally characterized them. The C-terminal domain showed strong PPIase activity, no role in histone chaperoning and revealed a monomeric five-beta palm-like fold that wrapped over a helix, typical of an FK506-binding domain. The N-terminal domain had a pentameric nucleoplasmin-fold; making this the first report of a plant nucleoplasmin structure. Further characterization revealed the N-terminal nucleoplasmin domain to interact with H2A/H2B and H3/H4 histone oligomers, individually, as well as simultaneously, suggesting two different binding sites for H2A/H2B and H3/H4. The pentameric domain assists nucleosome assembly and forms a discrete complex with pre-formed nucleosomes; wherein two pentamers bind to a nucleosome.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / chemistry
  • Arabidopsis / genetics
  • Arabidopsis Proteins / chemistry
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / ultrastructure*
  • Binding Sites / genetics
  • Chromatin Assembly and Disassembly / genetics
  • Crystallography, X-Ray
  • Histones / chemistry
  • Histones / genetics*
  • Molecular Chaperones / chemistry
  • Molecular Chaperones / genetics
  • Molecular Chaperones / ultrastructure*
  • Nucleoplasmins / chemistry*
  • Nucleoplasmins / genetics
  • Nucleosomes / chemistry
  • Nucleosomes / genetics
  • Peptidylprolyl Isomerase / genetics
  • Protein Binding / genetics
  • Protein Domains / genetics
  • Protein Folding
  • Tacrolimus Binding Proteins / chemistry
  • Tacrolimus Binding Proteins / genetics
  • Tacrolimus Binding Proteins / ultrastructure*

Substances

  • Arabidopsis Proteins
  • FKBP53 protein, Arabidopsis
  • Histones
  • Molecular Chaperones
  • Nucleoplasmins
  • Nucleosomes
  • Tacrolimus Binding Proteins
  • Peptidylprolyl Isomerase