Crystal Structures of Mutant Forms of the Yeast F1 ATPase Reveal Two Modes of Uncoupling

Diana Arsenieva,Jindrich Symersky,Yamin Wang,Vijayakanth Pagadala,David M Mueller

doi:10.1074/jbc.m110.174383

Diana Arsenieva, Jindrich Symersky + Show 3 more

Open Access

https://doi.org/10.1074/jbc.m110.174383

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Abstract

The mitochondrial ATP synthase couples the flow of protons with the phosphorylation of ADP. A class of mutations, the mitochondrial genome integrity (mgi) mutations, has been shown to uncouple this process in the yeast mitochondrial ATP synthase. Four mutant forms of the yeast F(1) ATPase with mgi mutations were crystallized; the structures were solved and analyzed. The analysis identifies two mechanisms of structural uncoupling: one in which the empty catalytic site is altered and in doing so, apparently disrupts substrate (phosphate) binding, and a second where the steric hindrance predicted between γLeu83 and β(DP) residues, Leu-391 and Glu-395, located in Catch 2 region, is reduced allowing rotation of the γ-subunit with less impedance. Overall, the structures provide key insights into the critical interactions in the yeast ATP synthase involved in the coupling process.

Highlights

The ATP synthase is composed of two distinct components, the F1 and the Fo portion and as such is referred to as the F1Fo ATP synthase
The high resolution structure of the bovine enzyme [1] established the naming convention of the three active sites in F1: DP, TP, and E, where DP refers to the ADP-bound site, TP refers to the ATP-bound site, and E refers to the catalytic site that has no nucleotide bound
The structure of yF1II identified the residues involved in binding phosphate [16]. yF1II likely represents the structure of the yF1 with one of the substrates for ATP synthesis, phosphate, bound to the active site

Summary

Introduction

The ATP synthase is composed of two distinct components, the F1 and the Fo portion and as such is referred to as the F1Fo ATP synthase. Residues ␣Phe405 and Structure of Mutant Forms of yF1I versus yF1II—The struc␤Arg408 (Fig. 1C) were both identified in the mgi screen and tural differences between yF1I and yF1II in the structures of the are located at the interface of the ␣- and ␤-subunits in the wild type enzyme were not consistently observed with each of

Results

Conclusion