N-terminal domain of human Hsp90 triggers binding to the cochaperone p23

Elif Karagoz, Afonso dos santos Duarte, Hans Ippel, Charlotte Uetrecht, Tessa Sinnige, Martijn Van Rosmalen, J. Hausmann, Albert J. R. Heck, Rolf Boelens, Stefan G. D. Rüdiger

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

The molecular chaperone Hsp90 is a protein folding machine that is conserved from bacteria to man. Human, cytosolic Hsp90 is dedicated to folding of chiefly signal transduction components. The chaperoning mechanism of Hsp90 is controlled by ATP and various cochaperones, but is poorly understood and controversial. Here, we characterized the Apo and ATP states of the 170-kDa human Hsp90 full-length protein by NMR spectroscopy in solution, and we elucidated the mechanism of the inhibition of its ATPase by its cochaperone p23. We assigned isoleucine side chains of Hsp90 via specific isotope labeling of their δ-methyl groups, which allowed the NMR analysis of the full-length protein. We found that ATP caused exclusively local changes in Hsp90’s N-terminal nucleotide-binding domain. Native mass spectrometry showed that Hsp90 and p23 form a 2∶2 complex via a positively cooperative mechanism. Despite this stoichiometry, NMR data indicated that the complex was not fully symmetric. The p23-dependent NMR shifts mapped to both the lid and the adenine end of Hsp90’s ATP binding pocket, but also to large parts of the middle domain. Shifts distant from the p23 binding site reflect p23-induced conformational changes in Hsp90. Together, we conclude that it is Hsp90’s nucleotide-binding domain that triggers the formation of the Hsp902p232 complex. We anticipate that our NMR approach has significant impact on future studies of full-length Hsp90 with cofactors and substrates, but also for the development of Hsp90 inhibiting anticancer drugs.
Original languageEnglish
Pages (from-to)580-585
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume108
Issue number2
DOIs
Publication statusPublished - 11 Jan 2011

Keywords

  • Allostery
  • Asymmetry
  • Heat shock proteins
  • Methyl-transverse-relaxation optimized spectroscopy
  • Protein-protein interactions
  • adenine
  • adenosine triphosphatase
  • adenosine triphosphate
  • heat shock protein 90
  • isoleucine
  • protein p23
  • amino terminal sequence
  • article
  • binding site
  • conformational transition
  • isotope labeling
  • mass spectrometry
  • nuclear magnetic resonance spectroscopy
  • priority journal
  • protein analysis
  • protein binding
  • protein domain
  • protein structure
  • signal transduction
  • stoichiometry

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