1 Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Blacksburg, VA 24061, United States.
2 Department of Biochemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Blacksburg, VA 24061, United States.
3 Natural Products Discovery Institute, Doylestown, PA 18902, United States.
4 Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, Blacksburg, VA 24061, United States. Electronic address: dkingston@vt.edu.