Title

The effect of protein stability on the dynamics of an electron transfer protein

Presenter Information

Matthew Goldes

Presentation Type

Poster

Abstract

Proteins are oligomeric macromolecules composed of amino acid monomers. Mutating specific amino residues within a protein can alter its stability, which can be compared to the wild-type conformation. Cytochrome c (cytc) plays a key role in the electron transport chain of living organisms and is involved in the intrinsic pathway of apoptosis. The active site of cytc contains a heme group; the surrounding protein matrix is referred to as the heme crevice. My project is an investigative comparison of the effects of stability on the dynamics of human and spider monkey cytc. I have sequentially mutated human cytc to the spider monkey sequence using site-directed mutagenesis. I completed experiments measuring the global stability of each variant using circular dichroism spectrophotometry. The results from these experiments indicate no significant difference in stability between the human and spider monkey cytc variants. I have also completed pH titrations on each variant to observe changes in the local stability of the heme crevice. I expected the local stability of the spider monkey variant to be lower than that of the other variants, however the results indicate that interactions between other mutated residues stabilize the heme crevice of the spider monkey variant. The results of this project will aid in understanding which residues within the primary cytc sequence have the greatest effect on the observed changes in protein stability. This information will contribute to the study of protein folding and stability, and may help determine why proteins misfold in diseases such as Alzheimers.

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Apr 13th, 3:00 PM Apr 13th, 4:00 PM

The effect of protein stability on the dynamics of an electron transfer protein

UC Ballroom

Proteins are oligomeric macromolecules composed of amino acid monomers. Mutating specific amino residues within a protein can alter its stability, which can be compared to the wild-type conformation. Cytochrome c (cytc) plays a key role in the electron transport chain of living organisms and is involved in the intrinsic pathway of apoptosis. The active site of cytc contains a heme group; the surrounding protein matrix is referred to as the heme crevice. My project is an investigative comparison of the effects of stability on the dynamics of human and spider monkey cytc. I have sequentially mutated human cytc to the spider monkey sequence using site-directed mutagenesis. I completed experiments measuring the global stability of each variant using circular dichroism spectrophotometry. The results from these experiments indicate no significant difference in stability between the human and spider monkey cytc variants. I have also completed pH titrations on each variant to observe changes in the local stability of the heme crevice. I expected the local stability of the spider monkey variant to be lower than that of the other variants, however the results indicate that interactions between other mutated residues stabilize the heme crevice of the spider monkey variant. The results of this project will aid in understanding which residues within the primary cytc sequence have the greatest effect on the observed changes in protein stability. This information will contribute to the study of protein folding and stability, and may help determine why proteins misfold in diseases such as Alzheimers.