Cyclotransferase enzyme
Model of human gamma-glutamyl cyclotransferase:
http://www.ncbi.nlm.nih.gov/pubmed/18515354
Model created from Protein Data Bank entry 2RBH:
http://www.rcsb.org/pdb/explore.do?structureId=2RBH
STL created using VMD:
http://www.ks.uiuc.edu/Research/vmd/
The protein backbone is represented in "cartoon" form.