Title
Characterisation of the Carboxypeptidase G2 Catalytic Site and Design of New Inhibitors for Cancer Therapy
Author
Dhadchayini Jeyaharan, Carla Brackstone, James Schouten, Paul Davis, Ann M. Dixon
Year
2018
Journal
ChemBioChem
Abstract
The enzyme carboxypeptidase G2 (CPG2) is utilized in antibody directed enzyme pro‐drug therapy (ADEPT) to catalyze the formation of an active drug from an inert pro‐drug. Free CPG2 in the bloodstream must be inhibited before administration of the pro‐drug in order to avoid a systemic reaction in the patient. Although a few small‐molecule CPG2 inhibitors have been reported, none have been taken forward thus far. This lack of progress is due in part to a lack of structural understanding of the CPG2 active site as well as the absence of small molecules that can block the active site whilst targeting the complex for clearance. The work described here aimed to address both areas. We report the structural/functional impact of extensive point mutation across the putative CPG2 catalytic site and adjacent regions for the first time, revealing residues outside the catalytic region (K208A, S210A and T357A) crucial to enzyme activity. We also describe novel molecules that inhibit CPG2 whilst maintaining accessibility of galactosylated moieties aimed at targeting the enzyme for clearance. This work acts as a platform for future development of high‐affinity CPG2 inhibitors that occupy new chemical space and will advance the safe application of ADEPT in cancer treatment.
Instrument
J-1500
Keywords
Circular dichroism, Secondary structure, Thermal stability, Protein folding, Biochemistry