alexa Glutathione mediated regulation of oligomeric structure and functional activity of Plasmodium falciparum glutathione S-transferase.
Bioinformatics & Systems Biology

Bioinformatics & Systems Biology

Metabolomics:Open Access

Author(s): Tripathi T, Rahlfs S, Becker K, Bhakuni V

Abstract Share this page

Abstract BACKGROUND: In contrast to many other organisms, the malarial parasite Plasmodium falciparum possesses only one typical glutathione S-transferase. This enzyme, PfGST, cannot be assigned to any of the known GST classes and represents a most interesting target for antimalarial drug development. The PfGST under native conditions forms non-covalently linked higher aggregates with major population (approximately 98\%) being tetramer. However, in the presence of 2 mM GSH, a dimer of PfGST is observed. Recently reported study on binding and catalytic properties of PfGST indicated a GSH dependent low-high affinity transition with simultaneous binding of two GSH molecules to PfGST dimer suggesting that GSH binds to low affinity inactive enzyme dimer converting it to high affinity functionally active dimer. In order to understand the role of GSH in tetramer-dimer transition of PfGST as well as in modulation of functional activity of the enzyme, detailed structural, functional and stability studies on recombinant PfGST in the presence and absence of GSH were carried out. RESULTS: Our data indicate that the dimer - and not the tetramer - is the active form of PfGST, and that substrate saturation is directly paralleled by dissociation of the tetramer. Furthermore, this dissociation is a reversible process indicating that the tetramer-dimer equilibrium of PfGST is defined by the surrounding GSH concentration. Equilibrium denaturation studies show that the PfGST tetramer has significantly higher stability compared to the dimer. The enhanced stability of the tetramer is likely to be due to stronger ionic interactions existing in it. CONCLUSION: This is the first report for any GST where an alteration in oligomeric structure and not just small conformational change is observed upon GSH binding to the enzyme. Furthermore we also demonstrate a reversible mechanism of regulation of functional activity of Plasmodium falciparum glutathione S-transferase via GSH induced dissociation of functionally inactive tetramer into active dimers.
This article was published in BMC Struct Biol and referenced in Metabolomics:Open Access

Relevant Expert PPTs

Relevant Speaker PPTs

Peer Reviewed Journals
 
Make the best use of Scientific Research and information from our 700 + peer reviewed, Open Access Journals
International Conferences 2017-18
 
Meet Inspiring Speakers and Experts at our 3000+ Global Annual Meetings

Contact Us

 
© 2008-2017 OMICS International - Open Access Publisher. Best viewed in Mozilla Firefox | Google Chrome | Above IE 7.0 version
adwords