Fig. 3.

Different structures of the Ligase IV inhibitor, SCR7. (A) L189 as a human DNA ligase inhibitor. (B) Less stable parental SCR7 reported by Srivastava et al can get autocyclized into a more stable form (SCR7-R). (C) Having the same molecular weight, number of protons, molecular mass, and melting point. Pending dehydrogenation, SCR7-R gets converted into SCR7-G (D), the compound sold as SCR7 by XcessBio (SCR7-X), possessing a different molecular weight, number of protons, molecular mass, and melting point.