Structural studies of glutathione S-transferases from plants

Thom, Russell (2000) Structural studies of glutathione S-transferases from plants. PhD thesis, University of Glasgow.

Abstract

The aim of this thesis was to structurally characterise a range of plant GSTs to increase the understanding as to which structural features determine substrate specificity. During the course of this work, a total of ten plant GSTs from species including Maize, Wheat, Carnation, Petunia and Arabidopsis thaliana were overexpressed in E. coli. Nine of these overexpressed GSTs were purified the produce protein for crystallisation using a range of matrices such as Orange A agarose, S-hexyl glutathione and metal chelate followed by ion-exchange and/or gel filtration chromatography depending on the particular GST. Initial crystallisation conditions for seven of these purified GSTs were found by sparse matrix screening. Crystallisation conditions providing crystals suitable for X-ray diffraction experiments were determined for four of the GSTs under study. The data gained from these diffraction experiments enabled the solution of four different plant GST three-dimensional structures. The first structure to be solved was ZmGSTF1, a GST isoenzyme constitutively expressed in Maize. The second structure to be solved was AtGSTZ1 from Arabidopsis thaliana. The third GST structure determined (AtGSTT1), again from Arabidopsis thaliana, was found to share significant homology with the mammalian Theta class GSTs. The fourth structure determined was a GST isoenzyme from wheat, able to metabolise the commercially important herbicide fenoxaprop. These structural models provide a detailed understanding of the structure determinants of a variety of GSTs which dictate the different substrate specificities of GSTs and provide suggestions for the rational design of GSTs to improve herbicide selectivity in crops. In addition, this study presents material relating to the in-vivo role of plant GSTs and their binding to endogenous substrates.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Subjects: Q Science > Q Science (General)
• Colleges/Schools: College of Medical Veterinary and Life Sciences
• Supervisor's Name: Lapthorn, Dr. Adrian
• Date of Award: 2000
• Depositing User: Miss Louise Annan
• Unique ID: glathesis:2000-6648
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 27 Aug 2015 09:03
• Last Modified: 27 Aug 2015 09:03
• URI: https://theses.gla.ac.uk/id/eprint/6648