Paper Citing NAMD - Abstract
Raghunathan, Devanathan; Gayen, Shovanlal; Grueber, Gerhard; Verma, Chandra S.
Crosstalk along the Stalk: Dynamics of the Interaction of Subunits B and F in the A(1)A(O) ATP Synthase of Methanosarcina mazei Gol
BIOCHEMISTRY, 49:4181-4190, MAY 18 2010
The mechanism of coupling of ion pumping in the membrane-bound A(O) sector with ATP synthesis in the A(3)B(3) headpiece of the A(1) sector in the A(1)A(O) ATP synthase is a puzzle. Previously, crosstalk between the stalk and nucleotide-binding subunits F-Mm and B-Mm of the Methanosarcina mazei Gol A-ATP synthase has been observed by nucleotide-dependent cross-link formation of both subunits inside the enzyme. The recently determined NMR solution structure of F-Mm depicts the protein as a two-domain structure, with a well-folded N-terminus having 78 residues and a flexible C-terminal part (residues 79-101), proposed to become structured after binding to its partner, B-Mm. Here, we detail the crucial interactions between subunits B-Mm and F-Mm by determining the NMR structure of the very C-terminus of F-Mm, consisting of 20 residues and hereafter termed FMm(81-101), and performing molecular dynamics simulations on the resulting structure. These data demonstrate that the flexibility of the C-terminus enables F-Mm to switch between an elongated and retracted state. Docking and MD in conjunction with previously conducted and published NMR results, biochemical cross-linking, and fluorescence spectroscopy data were used to reconstruct a model of a B-Mm-F-Mm assembly. The model of the B-Mm-F-Mm complex shows the detailed interactions of helices 1 and 2 of the C-terminal domain of B-Mm with the C-terminal residues of F-Mm. Movements of both helices of B-Mm accommodate the incoming C-terminus of From and connect the events of ion pumping and nucleotide binding in the A(1)A(O) ATP synthase.
