Structure of a compact conformation of linear diubiquitin

Acta Crystallogr D Biol Crystallogr. 2012 Feb;68(Pt 2):102-8. doi: 10.1107/S0907444911051195. Epub 2012 Jan 13.

Abstract

Post-translational modifications involving ubiquitin regulate a wide range of biological processes including protein degradation, responses to DNA damage and immune signalling. Ubiquitin polymerizes into chains which may contain eight different linkage types; the ubiquitin C-terminal glycine can link to one of the seven lysine residues or the N-terminal amino group of methionine in the distal ubiquitin molecule. The latter head-to-tail linkage type, referred to as a linear ubiquitin chain, is involved in NF-κB activation through specific interactions with NF-κB essential modulator (NEMO). Here, a crystal structure of linear diubiquitin at a resolution of 2.2 Å is reported. Although the two ubiquitin moieties do not interact with each other directly, the overall structure adopts a compact but not completely closed conformation with a few intermoiety contacts. This structure differs from the previously reported extended conformation, which resembles Lys63-linked diubiquitin, suggesting that the linear polyubiquitin chain is intrinsically flexible and can adopt multiple conformations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Crystallography, X-Ray
  • Humans
  • Lysine / chemistry
  • Lysine / metabolism
  • Models, Molecular
  • NF-kappa B / metabolism
  • Protein Conformation
  • Ubiquitins / chemistry*
  • Ubiquitins / metabolism

Substances

  • NF-kappa B
  • UBD protein, human
  • Ubiquitins
  • Lysine

Associated data

  • PDB/3AXC