We thank

The National Institutes of Health and the National Institute of General Medical Sciences (R01 GM085322)
The National Science Foundation (CHE-0845063 and CHE-1212692)
The American Cancer Society (RSG-12-253-01-CDD)
The American Chemical Society Petroleum Research Fund (46778-G)
The Robert H. Lurie Comprehensive Cancer Center (ACS-IRG 93-037-15)
Northwestern University

for generous support of our research.