Title: Glutathione transferase P1-1 as an arsenic drug-sequestering enzyme
Authors: Parker, LJ
Bocedi, A
Ascher, DB
Aitken, JB
Harris, HH
Lo Bello, M
Ricci, G
Morton, CJ
Parker, MW
Issue Year: 2017
Series Protein Sci.:
Abstract Arsenic-based compounds are paradoxically both poisons and drugs. Glutathione transferase (GSTP1-1) is a major factor in resistance to such drugs. Here we describe using crystallography, X-ray absorption spectroscopy, mutagenesis, mass spectrometry, and kinetic studies how GSTP1-1 recognizes the drug phenylarsine oxide (PAO). In conditions of cellular stress where glutathione (GSH) levels are low, PAO crosslinks C47 to C101 of the opposing monomer, a distance of 19.9 angstrom, and causes a dramatic widening of the dimer interface by approximately 10 angstrom. The GSH conjugate of PAO, which forms rapidly in cancerous cells, is a potent inhibitor (K-i=90 nM) and binds as a di-GSH complex in the active site forming part of a continuous network of interactions from one active site to the other. In summary, GSTP1-1 can detoxify arsenic-based drugs by sequestration at the active site and at the dimer interface, in situations where there is a plentiful supply of GSH, and at the reactive cysteines in conditions of low GSH. PDB Code(s): ; ; ;
URI: https://publications.svi.edu.au/publications/6331
Other Identifiers 10.1002/pro.3084
Publication type Article