Conformational transitions regulate the exposure of a DNA-binding domain in the RuvBL1-RuvBL2 complex

Nucleic Acids Res. 2012 Nov;40(21):11086-99. doi: 10.1093/nar/gks871. Epub 2012 Sep 21.


RuvBL1 and RuvBL2, also known as Pontin and Reptin, are AAA+ proteins essential in small nucleolar ribonucloprotein biogenesis, chromatin remodelling, nonsense-mediated messenger RNA decay and telomerase assembly, among other functions. They are homologous to prokaryotic RuvB, forming single- and double-hexameric rings; however, a DNA binding domain II (DII) is inserted within the AAA+ core. Despite their biological significance, questions remain regarding their structure. Here, we report cryo-electron microscopy structures of human double-ring RuvBL1-RuvBL2 complexes at ∼15 Å resolution. Significantly, we resolve two coexisting conformations, compact and stretched, by image classification techniques. Movements in DII domains drive these conformational transitions, extending the complex and regulating the exposure of DNA binding regions. DII domains connect with the AAA+ core and bind nucleic acids, suggesting that these conformational changes could impact the regulation of RuvBL1-RuvBL2 containing complexes. These findings resolve some of the controversies in the structure of RuvBL1-RuvBL2 by revealing a mechanism that extends the complex by adjustments in DII.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATPases Associated with Diverse Cellular Activities
  • Carrier Proteins / chemistry*
  • Carrier Proteins / metabolism
  • Carrier Proteins / ultrastructure
  • Cryoelectron Microscopy
  • DNA Helicases / chemistry*
  • DNA Helicases / metabolism
  • DNA Helicases / ultrastructure
  • DNA-Binding Proteins / chemistry*
  • DNA-Binding Proteins / ultrastructure
  • Humans
  • Models, Molecular
  • Protein Conformation
  • Protein Structure, Tertiary


  • Carrier Proteins
  • DNA-Binding Proteins
  • ATPases Associated with Diverse Cellular Activities
  • DNA Helicases
  • RUVBL1 protein, human
  • RUVBL2 protein, human