Department of Physiology Seminar Series
Joachim Weber, Ph.D.
Assistant Professor
Texas Tech University
Department of Chemistry & Biochemistry
Room ACB240, 3:30-4:30 p.m., Tuesday, June 12, 2007
“ATP Synthase – The World’s Smallest Rotary Motor”
ATP is the fuel for energy-requiring processes in all organisms. Every day the human body produces
approximately its own weight in ATP. The enzyme ATP synthase is responsible for the bulk of ATP
synthesis. It uses a transmembrane proton gradient to synthesize ATP from ADP and inorganic
phosphate, and it hydrolyses ATP to transport protons across the membrane. ATP synthesis/ hydrolysis
and proton translocation are tightly coupled by a unique mechanism, subunit rotation, making ATP
synthase a very efficient rotary nanomotor. The long-term goal of Dr. Weber’s research is to understand
the mechanism of ATP synthase in molecular detail.
Working with Dr. Alan Senior (University of Rochester, NY), Dr. Weber developed fluorescence-based
assays for protein-ligand and protein-protein interactions in ATP synthase. Tryptophan residues in the
three catalytic nucleotide binding sites were used as probes to monitor site occupancy by ATP and ADP,
leading to a model for the mechanism of ATP synthase. Tryptophan fluorescence and site-directed
mutagenesis were applied to investigate the contacts between subunits that hold the enzyme together
during subunit rotation.
Currently, Dr. Weber’s work focuses on the question how ATP binding and hydrolysis in the catalytic site
drive subunit rotation, using a variety of approaches. The applied techniques range from molecular
biology (site-directed mutagenesis) to biochemistry (protein chemistry, enzyme kinetics) to biophysical
chemistry (fluorescence spectroscopy). Molecular dynamics simulations and torque measurements by
single-molecule analysis are performed in collaboration with other laboratories.
Recent Publications
“Structural characterization of the interaction of the d and a subunits of the Escherichia coli F1F0-ATP synthase by
NMR spectroscopy”, Wilkens, S.; Borchardt, D.; Weber, J.; Senior, A.E. Biochemistry 2005, 44, 11786–11794.
"Happy Motoring with ATP Synthase", Senior, A.E.; Weber, J. Nature Struct. Mol. Biol. 2004, 11, 110-112.
“Fluorescent Probes Applied to Catalytic Cooperativity in ATP Synthase”, Weber, J.; Senior, A. E. Methods
Enzymol. 2004, 380, 132-152.
Persons with disabilities who may need auxiliary aids or services are requested to contact Josie Martinez at least 24 hours prior to
this seminar so that appropriate arrangements can be made.
Department of Physiology: Josie Martinez
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