Abstract |
Onchocerciasis is a debilitating parasitic disease caused by the filarial worm Onchocerca volvulus. Similar to other helminth parasites, O. volvulus is capable of evading the host's immune responses by a variety of defense mechanisms, including the detoxification activities of the glutathione S- transferases ( GSTs). Additionally, in response to drug treatment, helminth GSTs are highly up-regulated, making them tempting targets both for chemotherapy and for vaccine development. We analyzed the three-dimensional x-ray structure of the major cytosolic GST from O. volvulus (Ov-GST2) in complex with its natural substrate glutathione and its competitive inhibitor S-hexylglutathione at 1.5 and 1.8 angstrom resolution, respectively. From the perspective of the biochemical classification, the Ov-GST2 seems to be related to pi-class GSTs. However, in comparison to other pi-class GSTs, in particular to the host's counterpart, the Ov-GST2 reveals significant and unusual differences in the sequence and overall structure. Major differences can be found in helix alpha-2, an important region for substrate recognition. Moreover, the binding site for the electrophilic co-substrate is spatially increased and more solvent-accessible. These structural alterations are responsible for different substrate specificities and will form the basis of parasite-specific structure-based drug design investigations.
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Authors | Markus Perbandt, Jana Höppner, Christian Betzel, Rolf D Walter, Eva Liebau |
Journal | The Journal of biological chemistry
(J Biol Chem)
Vol. 280
Issue 13
Pg. 12630-6
(Apr 01 2005)
ISSN: 0021-9258 [Print] United States |
PMID | 15640152
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Glutathione Transferase
- Glutathione
- hexylglutathione
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Topics |
- Amino Acid Sequence
- Animals
- Crystallography, X-Ray
- Cytosol
(enzymology, metabolism)
- Escherichia coli
(metabolism)
- Glutathione
(analogs & derivatives, chemistry)
- Glutathione Transferase
(chemistry, metabolism)
- Humans
- Models, Molecular
- Molecular Sequence Data
- Onchocerca volvulus
(enzymology, metabolism)
- Placenta
(enzymology)
- Protein Conformation
- Protein Structure, Secondary
- Protein Structure, Tertiary
- Sequence Homology, Amino Acid
- Up-Regulation
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