This activity was designed as an in-class group activity, in which students begin by using basic principles to predict relative toxicities and roles of metals in biological systems. Students then learn about the structures of metallothioneins using information from the protein data bank (PDB) and 113Cd NMR data. By the end of the activity, students will have analyzed data to identify and determine bonding models and coordination sites for multiple cadmium centers in metallothioneins. It is based on recent literature, but does not require students to have read the papers before class.
Students will be able to:
- Use fundamental principles to predict toxicities of metals
- Apply hard-soft acid-base (HSAB) theory to metals in biological systems
- Utilize the protein data bank (PDB) to investigate protein-metal interactions
- Explain the roles of metallothioneins in biological systems
- Evaluate 1-D and 2-D 113Cd NMR to determine structures of Cd bonding sites in metallothioneins
- Explain how NMR can be utilized to determine protein structure
This activity was developed for a Master's level bioinorganic course, but could be utilized in an advanced undergraduate inorganic course. Students were given the worksheet at the beginning of class and worked together in groups to answer the questions. Students did not have access to the paper and had not read any articles previously. Using the PDB was done as a separate in-class activity, so students had some familiarity with the PDB codes and amino acid sequences.
A brief refresher of [1H-1H] COSY was presented before beginning the activity.
Students were evaluated by the instructor during the activity. The instructor was available throughout the activity to answer questions and guide inquiry. This activity generated good discussion among students and most were able to work their way through.
All students completed the activity during the class period and gained a deeper appreciation for metals in biology, protein structure, and using NMR to determine protein structure. Some students needed more guiding through the rationales of metal toxicities and the multi-dimensional NMR experiments than others.