1. NSF Center for Biocatalysis and Bioprocessing of Macromolecules, Othmer Department of Chemical and Biological Science and Engineering, Polytechnic University, 6 Metrotech Center, Brooklyn, NY 11201
2. National Synchrotron Light Source, Brookhaven National Laboratory, Upton, NY 11973
3. Corresponding author: http://chem.poly.edu/gros