Structural Factors Affecting the Rate of the Reaction Between Singlet Oxygen and Proteins

Presenter Information

Danielle Hron, Minnesota State University - MankatoFollow

Location

CSU Ballroom

Start Date

21-4-2014 10:00 AM

End Date

21-4-2014 11:30 AM

Student's Major

Chemistry and Geology

Student's College

Science, Engineering and Technology

Mentor's Name

John Thoemke

Mentor's Email Address

john.thoemke@mnsu.edu

Mentor's Department

Chemistry and Geology

Mentor's College

Science, Engineering and Technology

Description

Reactions between singlet oxygen and proteins are important to many biological processes including cell death. To study aspects of this process, reactions between singlet oxygen and free amino acids are examined. Under visible light irradiation, Rose Bengal (RB) photosensitizes singlet oxygen production and furfuryl alcohol (FFA) is used as a molecular probe to measure singlet oxygen concentration. As irradiation proceeds, the concentration of FFA diminishes due to the reaction with singlet oxygen. When added to the irradiated solution, an amino acid that reacts with singlet oxygen will compete with FFA, and the rate of FFA consumption will decrease. Using a kinetic model, rate constants for the reactions between amino acids and singlet oxygen are determined. A similar approach is used to study the reaction between singlet oxygen and intact proteins including lysozyme, bovine serum albumin, and glyceraldehyde 3-phosphate dehydrogenase. These proteins were selected based on the location of amino acid residues that potentially react with singlet oxygen, allowing a test of the hypothesis that “accessible” residues located on the exterior surface of the protein are more reactive than residues that are “buried” in the interior of the protein structure. The measurement results are compared to predictions based upon a computational model of the relative accessibility of each residue within the protein structure.