1bx9
From Proteopedia
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GLUTATHIONE S-TRANSFERASE IN COMPLEX WITH HERBICIDE
Overview
BACKGROUND: Glutathione S-transferases (GSTs) are detoxifying enzymes, present in all aerobic organisms. These enzymes catalyse the conjugation, of glutathione with a variety of electrophilic compounds. In plants, GSTs, catalyse the first step in the degradation of several herbicides, such as, triazines and acetamides, thus playing an important role in herbicide, tolerance. RESULTS: We have solved the structures of GST-I from maize in, complex with an atrazine-glutathione conjugate (at 2.8 A resolution) and, GST from Arabidopsis thaliana (araGST) in complex with an, FOE-4053-glutathione conjugate (at 2.6 A resolution). These ligands are, products of the detoxifying reaction and are well defined in the electron, density. The herbicide-binding site (H site) is different in the two, structures. The architecture of the glutathione-binding site (G site) of, araGST is different to that of the previously described structure of GST, in complex with two S-hexylglutathione molecules, but is homologous to, that of GST-I. CONCLUSIONS: Three features are responsible for the, differences in the H site of the two GSTs described here: the exchange of, hydrophobic residues of different degrees of bulkiness; a slight, difference in the location of the H site; and a difference in the degree, of flexibility of the upper side of the H site, which is built up by the, loop between helices alpha4 and alpha5. Taking these two structures as a, model, the different substrate specificities of other plant GSTs may be, explained. The structures reported here provide a basis for the design of, new, more selective herbicides.
About this Structure
1BX9 is a Single protein structure of sequence from Arabidopsis thaliana. Full crystallographic information is available from OCA.
Reference
Structures of herbicides in complex with their detoxifying enzyme glutathione S-transferase - explanations for the selectivity of the enzyme in plants., Prade L, Huber R, Bieseler B, Structure. 1998 Nov 15;6(11):1445-52. PMID:9817846
Page seeded by OCA on Tue Nov 20 11:59:32 2007
