Henry Weiner
Professor of Biochemistry
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Area |
Protein trafficking and the enzymology of aldehyde dehydrogenase |
| Office
| BCHM 305 |
| Phone
| (765) 494-1650 |
| Email
| hweiner@purdue.edu |
| Degree |
Ph.D. Purdue University, 1963 |
The laboratory is investigating two seemingly unrelated problems, which actually are related for each employ the tools of molecular and structural biology. The first is involved with the import of proteins into mitochondria. The second with structure and functional analysis of aldehyde dehydrogenase, a detoxifying enzyme found in all tissue and species.
 For a protein to be imported into mitochondria it must possess an N-terminal signal sequence, composed of 17-25 amino acids. After import the signal is removed in most cases by the action of a protease. We are interested in learning how the signals which all have different primary sequences can all be imported by the same translocators and processed by the same protease. Two approaches are employed to investigate the problem. One is to make mutations in the signal region and study their affect on the processes. The second is to study the interaction of synthetic signal peptides with a variety of components, including liposomes and proteins. For the later, physical techniques including 2D-NMR, CD, and fluorescence are employed. We are cloning components of the translocator so they can be characterized and incorporated into liposomes to reconstitute the translocator and identify new ones using a yeast two-hydrid system. In addition, a new co-translational import model is being developed.
The enzymology of aldehyde dehydrogenase is being investigated using various tools of molecular biology to probe for the active site of the enzyme. In collaboration with an X-ray chrystallographer, we recently determined the three dimensional structure of the enzyme. Projects include deleting the genes coding for the yeast enzyme so that this yeast can be used to produce mutants of the enzyme. The enzyme is being cloned in HeLa cells so we can study properties of the enzyme in vivo. Lastly, chimeric forms of the cytosolic and mitochondrial isozymes are being constructed in an attempt to understand why they have different properties. Allosteric interactions have been engineered into the enzyme, and we are studying them and subunit interactions. The aim is to try to be able to design an enzyme with properties not found in either parent enzyme which will be used to transform cells so they can be protected against the action of cytotoxic agents used in chemo-therapy. Directed evolution is being performed to produce enzymes with altered specificity.
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