Graduate Program
Chemistry
Degree Name
Master of Science (MS)
Semester of Degree Completion
2007
Thesis Director
Scott Tremain
Thesis Committee Member
Mark McGuire
Thesis Committee Member
Rebecca Peebles
Thesis Committee Member
Daniel Sheeran
Abstract
The objective of this thesis is to address the question of whether the removal of the native iron(II) ion in cytochrome c (cyt c) and substitution by a different metal ion affects the overall structural stability. We have studied the incorporation of zinc(II) into metal-free porphyrin cytochrome с (H2cyt) and investigated the structural stability of cyt c in the absence of the iron(II) ion and in the presence of the zinc(II) ion by different spectroscopic techniques. Compared to H2cyt, zinc-substituted cytochrome c (Zncyt) has a significantly different absorbance spectrum, so we monitor over time the change in absorbance upon addition of a zinc(II) ion. The rate of zinc(II) incorporation was studied under different denaturant conditions, such as urea and temperature, which unfolds the H₂cyt increasing porphyrin ring accessibility to zinc(II) incorporation.
The results of this study show a clear correlation between increasing temperature and the rate of incorporation of zinc(II) into H2cyt. At low temperatures, the zinc(II) incorporation is much slower, indicating partial unfolding of H2cyt, whereas at high temperatures the incorporation of zinc(II) into H2cyt is rapid due to the complete unfolding of H₂cyt facilitating the penetration of zinc(II) into the buried porphyrin ring. We also studied the effect of zinc(II) acetate concentration on the rate of incorporation of zinc(II) into H2cyt. At lower concentrations of zinc(II) acetate, the rate of incorporation is slow indicating that less zinc(II) was present for incorporation, whereas at higher concentrations of zinc(II) acetate the incorporation is rapid indicating that excess amounts of zinc(II) favor incorporation.
Recommended Citation
Potula, Sireesha, "Zinc(Ii) Incorporation Into Porphyrin Cytochrome C As A Function Of Temperature, Urea Concentration And Zinc(Ii) Acetate Concentration And The Urea And Guanidine Hydrochloride Induced Unfolding Of Porphyrin Cytochrome C" (2007). Masters Theses. 71.
https://thekeep.eiu.edu/theses/71
