Subunit F modulates ATP binding and migration in the nucleotide-binding subunit B of the A(1)A(O) ATP synthase of Methanosarcina mazei Gö1

J Bioenerg Biomembr. 2012 Feb;44(1):213-24. doi: 10.1007/s10863-012-9410-y. Epub 2012 Feb 14.

Abstract

The interaction of the nucleotide-binding subunit B with subunit F is essential in coupling of ion pumping and ATP synthesis in A(1)A(O) ATP synthases. Here we provide structural and thermodynamic insights on the nucleotide binding to the surface of subunits B and F of Methanosarcina mazei Gö1 A(1)A(O) ATP synthase, which initiated migration to its final binding pocket via two transitional intermediates on the surface of subunit B. NMR- and fluorescence spectroscopy as well as ITC data combined with molecular dynamics simulations of the nucleotide bound subunit B and nucleotide bound B-F complex in explicit solvent, suggests that subunit F is critical for the migration to and eventual occupancy of the final binding site by the nucleotide of subunit B. Rotation of the C-terminus and conformational changes in subunit B are initiated upon binding with subunit F causing a perturbation that leads to the migration of ATP from the transition site 1 through an intermediate transition site 2 to the final binding site 3. This mechanism is elucidated on the basis of change in binding affinity for the nucleotide at the specific sites on subunit B upon complexation with subunit F. The change in enthalpy is further explained based on the fluctuating local environment around the binding sites.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / biosynthesis*
  • Adenosine Triphosphate / metabolism*
  • Archaeal Proteins / genetics
  • Archaeal Proteins / metabolism*
  • Calorimetry
  • Methanosarcina / enzymology*
  • Models, Molecular*
  • Molecular Dynamics Simulation
  • Nuclear Magnetic Resonance, Biomolecular
  • Nucleotides / metabolism*
  • Protein Binding
  • Protein Subunits / genetics
  • Protein Subunits / metabolism*
  • Protein Transport
  • Proton-Translocating ATPases / genetics
  • Proton-Translocating ATPases / metabolism*
  • Spectrometry, Fluorescence
  • Thermodynamics

Substances

  • Archaeal Proteins
  • Nucleotides
  • Protein Subunits
  • Adenosine Triphosphate
  • A1A0 ATPase, Methanosarcina mazei
  • Proton-Translocating ATPases