1. Structure, function and regulation of the mitochondrial ATP synthase.

2. Structure and function of Cln3 - the gene defective in Batten Disease.

The Mitochondrial ATP Synthase

The research interest of this laboratory encompasses two distinct topics: protein structure and function as related to the mitochondrial ATP synthase and understanding the biochemical basis of Batten disease. Yeast Saccharomyces cerevisiae is used as a model organism because the enzyme is highly conserved from yeast to mammals and because of the powerful tools afforded by yeast.

The ATP synthase is a multimeric enzyme that is responsible for the synthesis of ATP via oxidative phosphorylation. The catalytic site is in a water-soluble portion of the enzyme, the F₁, which is bound to the membrane by a membrane bound portion, the F_o. The crystal structure of the water-soluble bovine F₁ portion was determined in the laboratory of Dr. John Walker at the Laboratory of Molecular Biology, Cambridge, U.K., making it one of the largest nonsymmetrical protein structures solved to date. In collaboration with Drs. John Walker and Andrew Leslie in the MRC in Cambridge, U.K., we now have the 2.8A map of the yeast F₁-ATPase. This is a major advance as it resnow allows us to investigate the structure/function relationship of the ATP synthase by a combination of genetic, biochemical, and x-ray crystallographic methods. Some of the aims that are being pursued are:

1. Reaction intermediates.

2. Inhibitor binding.

3. Mechanism of extragenic mutations that confer resistance to inhibitors.

These questions are being addressed using a combination of genetic, biochemical, x-ray crystallographic and cryo-EM methods. The yeast system is currently the only system available that can use all of these techniques to answer these questions.

Batten Disease

The Juvenile Form

A Neurodegenerative Disease

Cln3 gene

In 1995, JNCL disease gene was identified, Cln3.  Despite more than 23y of efforts, Cln3 is still classified as an “orphan gene”.  An orphan gene is a gene for which there is no know function of the gene product.  The Cln3 gene is conserved from human to yeast. Thus, we have an opportunity to understand the structure and function of the gene product with the use of yeast. Yeast gives us a number of tools that are not available with mammalian cell lines. We are approaching this problem by a combination of genetic and structural methods. We will exand our results from the yeast cell to the human cell.