Reference "Crystal structure of herbicide-detoxifying maize glutathione S-transferase-I in complex with lactoylglutathione: evidence for an induced-fit mechanism"

Reference ID

7213

Title

Crystal structure of herbicide-detoxifying maize glutathione S-transferase-I in complex with lactoylglutathione: evidence for an induced-fit mechanism

Source

Journal of molecular biology, 1997, vol. 274, pp. 446-453

Authors (5)

Neuefeind-T	Huber-R
Dasenbrock-H	Prade-L
Bieseler-B

Abstract

Glutathione S-transferases (GSTs) -I and -III are involved in herbicide
metabolism in maize and have been intensively studied. Starting with plant
tissue from Zea mays var. mutin recombinant GST-I was prepared by heterologous
expression in Escherichia coli. The enzyme was crystallized in the presence of
lactoylglutathione, a ligand formerly never observed in a GST structure and
known as an intermediate of the pharmacologically relevant glyoxalase system.
The crystal structure of GST-I has been determined at 2.5 A resolution and
exhibits the GST-typical dimer of two identical subunits, each consisting of 214
residues. Compared with other plant GSTs the three-dimensional structure of GST-
I primarily shows structural differences in the hydrophobic substrate binding
site, the linker segment and the C-terminal region. Furthermore, a comparison of
the ligand-bound GST-I structure with the apo structure of GST-III indicates the
movement of a ten-residue loop upon binding of the ligand to the active site.
This is the first structure-based evidence for an induced fit mechanism of
glutathione S-transferases, which has previously been postulated for class pi
enzymes. Together with GST-III, GST-I may explain herbicide resistance and
selectivity in maize as well as in other agronomic relevant crops.