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Effect of Substrate Binding Loop Mutations on the Structure, Kinetics, and Inhibition of Enoyl Acyl Carrier Protein Reductase from Plasmodium falciparum

Maity, Koustav and Banerjee, Tanushree and Prabakaran, Narayanappa and Surolia, Namita and Surolia, Avadhesha and Suguna, Kaza (2011) Effect of Substrate Binding Loop Mutations on the Structure, Kinetics, and Inhibition of Enoyl Acyl Carrier Protein Reductase from Plasmodium falciparum. In: IUBMB Life, 63 (1). pp. 30-41.

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Official URL: http://onlinelibrary.wiley.com/doi/10.1002/iub.412...

Abstract

Enoyl acyl carrier protein reductase (ENR), which catalyzes the final and rate limiting step of fatty acid elongation, has been validated as a potential drug target. Triclosan is known to be an effective inhibitor for this enzyme. We mutated the substrate binding site residue Ala372 of the ENR of Plasmodium falciparum (PfENR) to Methionine and Valine which increased the affinity of the enzyme towards triclosan to almost double, close to that of Escherichia coli ENR (EcENR) which has a Methionine at the structurally similar position of Ala372 of PfENR. Kinetic studies of the mutants of PfENR and the crystal structure analysis of the A372M mutant revealed that a more hydrophobic environment enhances the affinity of the enzyme for the inhibitor. A triclosan derivative showed a threefold increase in the affinity towards the mutants compared to the wild type, due to additional interactions with the A372M mutant as revealed by the crystal structure. The enzyme has a conserved salt bridge which stabilizes the substrate binding loop and appears to be important for the active conformation of the enzyme. We generated a second set of mutants to check this hypothesis. These mutants showed loss of function, except in one case, where the crystal structure showed that the substrate binding loop is stabilized by a water bridge network. (C) 2011 IUBMB mum Life, 63(1): 30-41,2011

Item Type: Journal Article
Keywords: P. falciparum; enoyl-ACP reductase; mutant; salt bridge; substrate binding loop; water bridge
Department/Centre: Division of Biological Sciences > Molecular Biophysics Unit
Depositing User: Id for Latest eprints
Date Deposited: 24 Mar 2011 06:42
Last Modified: 24 Mar 2011 06:42
URI: http://eprints.iisc.ac.in/id/eprint/36199

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