20 Jul 2012

Soluble Methane Monooxgenase Spectroscopy

In-Class Activity

Submitted by Gerard Rowe, University of South Carolina Aiken

Determining the reactive intermediates in metalloenzymes is a very involved task, and requires drawing from many different spectroscopies and physical methods.  The facile activation and oxidation of methane to produce methanol is one of the "holy grails" of inorganic chemistry.  Strategies exist within materials science and organometallic chemistry to activate methane, but using the enzyme methane monooxygenase, nature is able to carry out this difficult reaction at ambient temperatures and pressures (and in water, too!).  This activity asks students to look at the proposed catalytic cycle of soluble methane monooxygenase and choose an appropriate spectroscopic technique to provide different information about the various species in the process.

Learning Goals: 

The student will be able to identify the key features of a scheme describing a catalytic cycle's intermediates

The student will learn to think of spectroscopy as an experiment that operates within a specific time scheme instead of as a figure in a paper

The student will be able to explain the advantages and limitations of different spectroscopic techniques

The student will use their knowledge of spectroscopic techniques to decide the best method to obtain the desired information

Implementation Notes: 

I give this activity to students towards the end of my advanced inorganic chemistry course.  By this point, they have already been exposed to most of the major spectroscopic techniques used in inorganic chemistry, and have had several lectures in bioinorganic chemistry.  

Evaluation Methods: 

The activities are collected and graded based on how reasonable and well-supported their answers are.

Students also receive a question about inorganic spectroscopy on their final exam.

Evaluation Results: 

Students were generally successful at identifying the right spectroscopic technique for the job.  The most challenging problem was the one concerning spin states, especially because they have to consider all the coupling possibilities for each diiron species and remember what makes a compound EPR active/silent.


The final exam question had somewhat more mixed results, probably due to the fact that two weeks had elapsed in between this activity and the exam.

Creative Commons License: 
Creative Commons Licence


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