This is a computer-based activity intended for a bioinorganic chemistry course composed of upper-level undergraduate students. It is helpful for students to be familiar with concepts of electron transfer, including a surface-level introduction to Marcus theory and the inverted region, and photosynthetic charge separation before beginning this activity. However, this activity can easily be adapted to students with other levels of preparation in a bioinorganic course.
- Analyze the structure of a photosynthetic reaction center using PDB.
- Identify and evaluate high-probability electron transfer pathways using eMAP.
- Evaluate cofactors and amino acids that contribute to electron-transfer in proteins.
- Apply basic concepts from Marcus theory to describe charge separation.
- Write a report on the background and findings of this activity.
Computer with internet access.
I have only tested this activity in class once, and an unexpected result was students filling multiple pages of their report with images instead of carefully interlacing them into the text. If you have a strong preference for report formatting, you should modify the handout because it will not enforce a rigid formatting structure. I also allowed students to work together in groups of two, but in the future I will make this an assignment to be completed individually to better assess if the Learning Objectives were met by each student.
Before this activity, students had learned in class the basics of Marcus electron-transfer theory and photosynthetic charge separation. However, we had not discussed the role of amino acids in long-range electron transfer through proteins, so part of this activity was for students to use eMAP to "discover" that tyrosine and tryptophan are involved in the process too.
In the future I will likely not enforce this particular photosynthetic reaction center. Instead, I would like to allow students to chose a PDB entry on their own.
Regarding evaluations, I converted the items on the last page of the handout into a grading rubric in Canvas. The most heavily weighted components were the Introduction and the Analysis and Discussion sections. To evaluate these sections I based scores on the student's demonstration of achieving the Learning Objectives. This was a high-scoring activity because the scoring did not deduct points for formatting issues or minor grammar mistakes.