Quaternary structure of KATP channel SUR2A nucleotide binding domains resolved by synchrotron radiation X-ray scattering

Sungjo Park, Andre Terzic

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Heterodimeric nucleotide binding domains NBD1/NBD2 distinguish the ATP-binding cassette protein SUR2A, a recognized regulatory subunit of cardiac ATP-sensitive K+ (KATP) channels. The tandem function of these core domains ensures metabolism-dependent gating of the Kir6.2 channel pore, yet their structural arrangement has not been resolved. Here, purified monodisperse and interference-free recombinant particles were subjected to synchrotron radiation small-angle X-ray scattering (SAXS) in solution. Intensity function analysis of SAXS profiles resolved NBD1 and NBD2 as octamers. Implemented by ab initio simulated annealing, shape determination prioritized an oblong envelope wrapping NBD1 and NBD2 with respective dimensions of 168 × 80 × 37 Å3 and 175 × 81 × 37 Å3 based on symmetry constraints, validated by atomic force microscopy. Docking crystal structure homology models against SAXS data reconstructed the NBD ensemble surrounding an inner cleft suitable for Kir6.2 insertion. Human heart disease-associated mutations introduced in silico verified the criticality of the mapped protein-protein interface. The resolved quaternary structure delineates thereby a macromolecular arrangement of KATP channel SUR2A regulatory domains.

Original languageEnglish (US)
Pages (from-to)243-251
Number of pages9
JournalJournal of Structural Biology
Volume169
Issue number2
DOIs
StatePublished - Feb 2010

Fingerprint

KATP Channels
Synchrotrons
Nucleotides
X-Rays
Radiation
Adenosine Triphosphate
Atomic Force Microscopy
Computer Simulation
Heart Diseases
Carrier Proteins
Proteins
Mutation

Keywords

  • ATP-sensitive K channel
  • Kir6.2
  • Mutation
  • Small-angle X-ray scattering
  • Structure
  • SUR2A

ASJC Scopus subject areas

  • Structural Biology

Cite this

Quaternary structure of KATP channel SUR2A nucleotide binding domains resolved by synchrotron radiation X-ray scattering. / Park, Sungjo; Terzic, Andre.

In: Journal of Structural Biology, Vol. 169, No. 2, 02.2010, p. 243-251.

Research output: Contribution to journalArticle

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