Comparison between single-molecule and X-ray crystallography data on yeast F1-ATPase

Area of Science:

• Biochemistry
• Molecular Biology
• Biophysics

Background:

• Single molecule studies have detailed the F1-adenosine triphosphate synthase (F1-ATPase) chemo-mechanical cycle, primarily using bacterial enzymes.
• High-resolution crystal structures are limited to mitochondrial F1-ATPase.
• Yeast mitochondrial F1-ATPase offers a model for studying enzyme mechanisms.

Purpose of the Study:

• To present high-resolution single molecule rotational data for Saccharomyces cerevisiae mitochondrial F1-ATPase.
• To analyze wild-type, a
• liver
• isoform, and six mutant forms of yeast F1-ATPase.
• To correlate single molecule rotational data with existing crystal structure information.

Main Methods:

• High-throughput single molecule detection and analysis techniques.
• Rotational analysis of wild-type and mutant yeast F1-ATPase.
• Comparison of experimental data with crystal structure data.

Main Results:

• Wild-type and
• liver
• isoforms exhibit rotational behavior consistent with bacterial F1-ATPase.
• Mutant forms display a catalytic dwell delay and reduced Vmax, correlating with structural defects.
• A novel dwell at the ATP binding angle was observed in at least one mutant, suggesting impaired ADP release.

Conclusions:

• Single molecule rotational analysis provides insights into yeast mitochondrial F1-ATPase function.
• Enzyme kinetics and structural integrity are closely linked in F1-ATPase.
• This study bridges the gap between structural data and functional mechanisms of F1-ATPase.