Doing a quick Google search did not turn up a good description of prolyl isomerization.
Why was I searching for this?
My research lead me to the modification of Peptidyl-prolyl cis-trans isomerase FKBP1A, which has the activity of prolyl isomerization. Franz X. Schmid's lab at the University of Bayreuth published a paper in 2007 entitled Insertion of a Chaperone Domain Converts FKBP12 into a Powerful Catalyst of Protein Folding in which they describe the insertion of a domain from an E. coli FKBP analog SlyD into human FKBP. This improved its prolyl isomerase activity.
This activity is important because when a protein is folding, it is highly dependent on the orientation between the peptide bonds. For the folding of some proteins, prolyl isomerization is a rate liming factor. A prolyl isomerase can enzymatically assist the switch from a cis- to trans- isomeration of proline residues. This site that most helped me to visualize what cis- and trans- conformations are in terms of peptide bonds, and the structure of cis- and trans-forms of proline bonds was http://www.cryst.bbk.ac.uk/PPS95/course/3_geometry/peptide2.html.
Its all about the alpha carbon.
Happy protein folding!
